Downey Engine Conversion Manual

IMPORTANT THINGS YOU NEED TO KNOW BEFORE YOU START

This instruction manual has been produced for your convenience in
determining which Downey parts, what expenses, and what tools will be
required for your engine/transmission choice, and to instruct you in
performing the actual conversion. Over the years we have not only developed
more conversion components and choices, but we have also refined our
components to a state of perfection that insures ease of installation and
reliability that will last beyond the life of your vehicle.

USING THIS MANUAL

This manual is updated regularly, however GM occasionally changes their
part numbers without warning, which can cause some confusion when using
this manual. When reading each individual instruction, the instruction may
be alerting you to:

o Need for a tool you do not presently have.
o Need for additional parts, gaskets, bolts, etc.
o Need for additional expenses not anticipated.

After reading each instruction, think about these items and enter them on
your shopping list. When a particular GM part number is given. the part
required may have been supplied with your engine, and no additional expense
is required.

There may be more than one particular GM part that can be used, but if you
get into trouble experimenting, revert back to the part number specified in
this manual. We also recommend you obtain a Toyota shop manual to use in
conjunction with this manual once you begin your conversion. The Toyota
manual will give you torque values, wiring diagrams, and other valuable
information


ENGINE SELECTION

Buick 231 V-6 - These engines are the most popular because "THEY FlT."
They do not present serious oil pan problems, there is no firewall
clearance problem (distributor is mounted at the front of the engine), and
you will be able to retain your stock alternator, power steering pump, and
air conditioning compressor. These engines are a substantial cubic inch
gain, yet your drive train will hold up to fairly aggressive driving
without overstressing the drivetrain. You should be using a 1976 or newer
engine from a Buick, Pontiac, Oldsmobile or Cadillac.

Chevy Vortec V-6 - These engines are starting to become popular for Toyota
conversions because they are slightly larger than the Buick 231 (Buick is
3.8 liter, Chevy is 4.3 liter).

o You can not use the stock alternator, power steering pump, or air
conditioning compressor. GM components must be used and custom hoses or
adapters will be required (refer to Downey catalog).
o Oil pan clearance is a problem unless you have a suspension lift kit (IFS
models must have a Trailmaster or Rancho lift kit). 1986-newer Toyotas must
use a 1986-newer Vortec engine because a 1986-newer Chevy S-10 oil pan must
be used.

o There may be a clearance problem between the distributor and firewall
(depending upon transmission choice) unless you have a body lift kit.

o Once you overcome these problems the Vortec V-6 is very comfortable inside
your engine compartment, and can be driven in a reasonable manner without
overstressing the drivetrain. These engines can be found in 1981 and newer
Chevrolets only.

Small Block Chevy V-8 - These conversions are desirable because the power
gain is enormous, but installation also requires substantially more work
and expense. We are not in agreement with those who believe your stock
drivetrain will hold up to V-8 power, in fact we believe you must regulate
your driving habits considerably to protect the drivetrain.

o You must use GM alternator, power steering pump, and air conditioning
compressor. Custom hoses or adapters will be required (refer to Downey
catalog).

o You must have a suspension lift kit to eliminate oil pan clearance
problems. IFS models must have a Rancho or Trailmaster lift kit, or the
special oil pan listed in the Downey catalog (see instruction #30).

o You must have a body lift kit to eliminate firewall clearance problems at
the distributor and manifolds (see Note below).

o You must move the radiator forward approximately 2", manufacture your own
radiator mounting framework, and convert to pull-pin type hood latches (see
Note below).

o You must relocate the transfer-case mounting crossmember or cushion and
modify the drive shafts (see Note below).

NOTE - It is nearly impossible to predetermine exact clearances on V-8
conversions. The factors that influence this are:

o Length of transmission being used.
o Length of adapter being used.
o Firewall shape, differs between year models.
o Length of water pump, pulleys, fan (differs per engine).
o Thickness of radiator (yours or Downey's).
o Use of a suspension lift kit, amount of lift.
o Use of a 2" or 3" body lift kit.
o Size of distributor (diameter).

TRANSMISSION SELECTION

Downey offers kits for four transmission choices for your Toyota 4WD
Pickup or 4 Runner conversion:

'85-newer Stock Toyota 5 Speed - The 1979-84 Toyota 4 or 5 speed
transmissions were designed to withstand slightly more torque than the
stock 4 cylinder engine produces (4 Cyl. produces 120 ft. lbs. of torque,
the stock 4 or 5 speed will withstand 140 ft. lbs. of torque). A Buick 231
V-6 is the least powerful engine conversion we offer and they produce 195
ft. lbs. of torque. The 1985-newer Toyota 5 speed transmission has been
made heavier duty (stronger input bearing) and they can survive fairly well
provided you avoid power shifting. Most conversions using the 1985-newer 5
speed transmission require adjustments to the rear motor mount and/or drive
shafts.

Stock AW4 Automatic - The stock 1984-newer Toyota Automatic Transmission
can be used with a Chevy Vortec or V-6 conversion. Adaption is not
available for using this transmission with a Buick 231. This is the best
transmission choice when your vehicle was originally equipped with an
automatic transmission because the Toyota 5 speed or GM automatics are not
adaptable to your transfer-case.

Turbo 350 Automatic - These transmissions are approximately 3 times
stronger than a Toyota 4 or 5 speed transmission. They are the most popular
transmission choice because they have proven to work better in off road
terrain and they do not have to he pampered (these are the same
transmissions used in 6,000 to 8,000 lb. motorhomes and stakebeds).

Turbo 350 with Overdrive (TH7OOR-4) - These transmissions can be used in
1984-newer conversions, however these transmissions are 1.87" longer than a
standard T-350, consequently conversions that would not have required drive
shaft modifications with a standard T-350 will require modifications with
this transmission. Since all T-350 and 700R-4 transmissions that were
originally used in EFI computer controlled applications are equipped with a
lockup torque converter and many of them are computer controlled, you will
need to install a new torque converter lockup switch (Downey #32100-80217).
This switch must be used if you are using a carburated engine or TBI EFI
computer controlled engine in your conversion.


VEHICLE MODIFICATIONS

You may have already made some of the following modifications to your
vehicle. You may opt to perform some of these modifications before you
commence the engine conversion, while the engine compartment is empty, or
wait until after the GM engine is mounted into the vehicle.

Body Lift Kit - If installing a Buick 231, a body lift kit is not required.
If a Chevy V-8 or V-6 is being installed, a body lift kit may be required
for distributor to firewall clearance, and transmission to floorboard
clearance. Use of a body lift kit will also promote better
engine cooling because there is greater air passage clearance between
engine and sheet metal, which helps dissipate engine heat.

Suspension Lift Kit - 1979-85 vehicles should have a 3" suspension lift
kit. A lift kit will supply front drive shaft to starter clearance on Buick
and Chevy engine conversions, and differential to oil pan clearance on
Chevy conversions. 2" spacer blocks must be mounted below the frame on
Chevy conversions to limit differential travel. If you do not install 2"
spacer blocks, the torque rod mount on the differential housing will smash
into the oil pan. 1986-newer Buick 231 conversions do not require a body
lift kit, but you must use the shallow oil pan and dent the corner slightly
(see instruction #30). Chevy V-6 or V-S conversions must have a body lift
kit and Trailmaster or Rancho suspension lift kit, or use the special oil
pan listed in the Downey catalog.

Radiator Mounting - Buick and Chevy V-6 conversions will be using Downey's
V-6 radiator (or your stock radiator modified), which will mount into the
stock location. V-8 conversions are not as simple. You will be installing a
longer motor and using a thicker core radiator. In most cases your V-8
radiator must be mounted 1" to 2" forward of the original radiator mounting
location. This will necessitate cutting out an opening in your stock
radiator mounting panel large enough to house the V-8 radiator. You must
cut out the stock upper tie bar and remove the hood latch. You must
fabricate new radiator mounting brackets, fabricate a new tie bar (see
suggested configuration illustration on page 10), and convert to pull-pin
type hood latches. It may also be necessary to modify the front lower
crossmember on 1979-83 models. Another option we have seen used is to
position the V-8 engine rearward, with the distributor positioned inside
the transmission tunnel - good luck!

TOOLS REQUIRED

Your Toyota has been assembled with metric bolts. In addition to your
American sockets and wrenches, which will be required for the GM engine and
many of the adapter components, you should have a complete set of metric
sockets and wrenches.

You will need an engine hoist, available from most equipment rental
companies.
You will need a good floor jack with rollers.
Some installations will require 4 large C-clamps.

ENGINE CONVERSION INSTRUCTIONS
REMOVING THE ENGINE

1. Remove Hood.

2. Disconnect and remove battery, then disconnect all starter wires.

3. Loosen drain cocks and drain engine and radiator. Remove radiator hoses,
then remove radiator from vehicle.

4. Disconnect alternator wires, then remove alternator if alternator is
being installed on a Buick 231 engine.

5. Disconnect ground cables between engine, body, and frame.

6. Disconnect temperature and oil pressure sending unit wires from senders.
Mark these wires for future use.

7. Unplug oxygen sensor at the yellow plastic plug ('81-88 models) or from
the tail pipe ('89-newer models).

8. Locate the wire that connects to the positive post of the stock coil.
Mark this wire for future use. Remove stock coil and ignitor.

9. Disconnect throttle cable from engine.

10. Unplug/disconnect and remove smog device from inner fender apron.

11. Disconnect brake booster vacuum hose from intake manifold.

12. Disconnect and remove all heater hoses.

13. Disconnect slave cylinder plumbing at the firewall. If using a T-350
automatic transmission, remove clutch master cylinder, all plumbing, and
clutch pedal from vehicle.

14. Power Steering Pump 

o Buick 231 - If installing this engine, unbolt power steering pump from
your Toyota engine and tie to inner fender apron. Do not loosen or remove
hoses. 1979-80 models may completely remove pump since you will be using an
'81-newer pump.

o Chevy V-6 or V-8 - If installing this engine, completely remove power
steering pump and hoses since you will be using a GM pump and new hoses
and/or adapters.

15. Air Conditioning Compressor

o Buick 231 - If installing this engine, unbolt air conditioning
compressor from engine and tie to inner fender apron. Do not loosen or remove
hoses. 1979-83 models may completely remove compressor since you will be
using an '84-newer compressor.

o Chevy V-6 or V-8 - If installing this engine, completely remove compressor
and hoses since you will be using a GM compressor, mounting brackets and
hoses.

16. Disconnect speedometer cable and 4WD indicator light wiring from
transfer-case.

17. Disconnect and remove front and rear drive shafts. Reinstall the
special shoulder bolts so they will not become misplaced.

18. Remove entire exhaust system.

19. Remove transmission and transfer-case shift levers.

20. Attach a hoist to engine near rear of block, this will be a good
balance point.

21. Position a floor jack below transfer-case crossmember.

22. Remove nuts from front motor mount cushions. DO NOT loosen motor mounts
from side of engine.

23. Remove bolts from rear motor mount cushion. Raise jack slightly, unbolt
crossmember from frame, then lower jack.

24. Hoist the engine, transmission, and transfer-case out of the vehicle as
one piece.

PREPARING THE CONVERSION ENGINE

25. PULLEYS

o Buick 231 - You should be using water pump pulley GM #25522583 and crank
shaft pulley GM #25522581. These are the pulleys used for proper belt
alignment with Downey's alternator, power steering, and air conditioning
mounting hardware. Most Buick 231's come stock with these pulleys.

o Chevy V-6 or V-8 - You will be using GM alternator, power steering, and
air conditioning, therefore you should use any combination of matching GM
pulleys that establish belt alignment among those components. Radiator
clearance is critical on V-8 conversions, therefore you should be using the
"short" water pump and a 2 belt system instead of a 3 belt system.

26. FRONT MOTOR MOUNTS

o Buick 231 - Attach Downey motor mounts to the engine in the stock
mounting locations on the block. The alternator mounting configuration goes
on the left (driver's side). Remove stock cushions from the frame and
attach them to the block mounts loosely. Once engine is installed, stock
cushions can be tightened.

o '79-85 Chevy V-6 or V-8  The mounts supplied with these conversions
include gusseted ('L" brackets and triangular block brackets. The block
brackets are identical, right and left. Attach block brackets to the stock
motor mounting locations on the block.

o '86-newer Chevy Vortec V-6 - The mounts supplied with these conversions
require use of Chevy Astro Van block brackets and cushions. If your engine
was not supplied with Astro Van type motor mounts, obtain GM block brackets
(LH) #15596458 and (RH) #15596459, and two rubber cushions GM #14082803
(not supplied by Downey), and attach them to the stock motor mounting
locations on the block.

o '86- Newer Chevy V-8 - The mounts supplied with these conversions include
formed steel mounts that attach to the frame and route back to GM cushions
on the block. Attach GM #3990914 cushions (not supplied by Downey) to the
stock motor mounting locations on the block.


27.FUEL PUMP

o '75-79 Toyota - These Pickups with 20R engines have an approximate 5
p.s.i. fuel pump mounted inside the fuel tank. This pump can be used with
carburated GM engines, however, power to the in-tank pump will be lost when
the stock 20R smog device is unplugged. You must establish a new 12 volt
power supply to the fuel pump from a source which is active only when the
ignition switch is on.

o '80-newer Carburated Toyota - These Pickups and 4 Runners have a
conventional engine mounted fuel pump, which will be aborted during your
engine conversion. You must use either a conventional GM fuel pump or an
electric fuel pump.

o Buick 231 - These conversions require use of an electric fuel pump if
using a carburated engine. If your model was not equipped with an electric
fuel pump, install an electric fuel pump. Electric fuel pumps are pushers,
not suckers, so your pump mounting location should be near the tank, not
near the engine. A fuel pump block-off plate is available from a GM dealer
or speed shop. Install block-off plate and gasket onto stock mechanical
fuel pump mounting location on the timing housing.

o Chevy V-6 or V-8 - These conversions can use a stock GM mechanical fuel
pump if using a carburated engine. If your vehicle was originally equipped
with an electric fuel pump, you can retain the electric pump and install a
fuel pump block-off plate and gasket onto stock mechanical fuel pump
mounting location on the block, or you can install a mechanical fuel pump
and gasket.

o '84-newer EFI Toyota - These pickups and 4 Runners have an approximate 50
p.s.i. in-tank electric fuel pump. This pump can be used with ANY GM engine
conversion, however, a fuel pressure regulator and fuel return line must be
used for carburated or throttle body GM engines.
1.Carburated engines require about 5 p.s.i.
2.Throttle body engines TBI) require approximately 15 p.s.i.
3.Tuned port engines TPI) require approximately 50 p.s.i.

NOTE - When installing a throttle body or tuned port injected engine (TBI
or TPI), you will need a higher volume/higher pressure fuel pump. NEW high
volume in-tank or external fuel pumps are expensive (approximately
$300.00), however, there are numerous choices of used pumps that can be
used. A good example is a 1980-83 Toyota Supra 6 Cyl. or 1980-83 Toyota
Creseda 6 Cyl. out-of-tank electric fuel pump. These pumps or similar
out-of-tank fuel pumps can be purchased used, and do not require tank
modification or expensive in-tank mounting brackets. These pumps should be
mounted as close to the tank as possible for two reasons.

1. Electric fuel pumps are pushers, not suckers.
2. During hot temperatures the fuel system can vapor lock between the fuel
tank and fuel pump. Mounting the fuel pump as close to the tank as possible
will reduce the possibility of vapor lock.

28. TEMPERATURE SENDER

o Remove stock temperature sending unit from the stock intake manifold. You
must use the Toyota sending unit to ensure a correct reading at the dash.

o Buick 231 - Using Downey adapter #15809-R, install sending unit into V-6
intake manifold in the threaded hole that will position the sending unit
horizontally (pointing forward). This location should be closest to the
thermostat, and is necessary to insure sending unit is submerged in water
to prevent a false reading at the dash.

o Chevy V-6 or V-8 - Using Downey adapter #15609-F, install sending unit in
the GM intake manifold in the threaded hole near or behind the thermostat
housing.

29. OIL PRESSURE SENDER

Remove stock oil pressure switch from side of engine. You must use the
Toyota switch to ensure a correct reading at the dash.

o Buick 231  Remove oil pressure switch from V-6 block (located behind and
above oil filter). Using Downey fitting and thread sealant #87251-R,
install Toyota switch into V-6 block.

o Chevy V-6 or V-8 - Using Downey fittings and thread sealant #87251-F,
install Toyota switch into block in the threaded hole at the rear of the
block (beside distributor).

o TBI TPI Oil Pressure Sensor - GM computerized engines have an oil
pressure sensor that is used to signal the computer if oil pressure is
lost. The engine will not run if the oil pressure sensor is not connected,
You must obtain fittings from your local parts store that will allow
installation of both the oil pressure Sensor and Sender in a single T type
fitting. The Sensor should be mounted into a 1/4" pipe thread female
fitting, and the Sender should be mounted into a 1/8" pipe thread female
fitting.

30. OIL PAN

o Buick 231 - You can use any Buick 231 oil pan on '79-85 conversions You
must use the Jeep or Cadillac Eldorado type shallow oil pan on '86- newer
conversions, and slightly dent the front corner for front differential
housing clearance.

o Chevy V-6 or V-8 - You can use any rear sump oil pan on '79-85
conversions. You must install 2" limiting blocks under the frame rails to
prevent differential housing contact with the oil pan when bottomed,

o '86-newer Chevy Vortec V-6 - These conversions must use a Rancho or
Trailmaster lift kit, and a 1986-newer Chevy S-10 Vortec V-6 oil pan.

o '86-newer Chevy V-8 - These conversions must use a Rancho or Trailmaster
lift kit, or use the special oil pan listed in the Downey catalog.

ADAPTING 5 SPEED MANUAL TRANSMISSION TO ENGINE

31. Bolt new flywheel to crankshaft using special GM bolts and torque specs.

o Buick 231 - Use the 160 tooth flywheel, Downey #13405-R5B.

o Chevy V-6 or V-8 - On 1985-older internally balanced engines use GM
flywheel #14085720. On 1986-newer externally balanced engines use GM
flywheel #14088650.

32. Install new pilot bushing supplied with the bellhousing adapter into
back of crankshaft. NOTE - The length of the new bellhousing adapter will
determine the amount of engagement between transmission input shaft and
pilot bushing. When installing pilot bushing, you must ensure that the
"pilot" portion of the input shaft is seated into the pilot bushing at
least 318" minimum or fully seated maximum. It may be necessary to leave
the pilot bushing protruding out of the crank shaft approximately 1/4".

33. Install new pressure plate and clutch disc onto flywheel using special
GM bolts and torque specs. You must use the special Downey 21 spline 10"
clutch disc #31250-6105 and Downey pressure plate #31210-R5, or Centerforce
#CF361874. You can use your transmission input shaft (or Downey alignment
tool #31210-RT) to align the clutch disc with the pilot bushing before
tightening the pressure plate.

34. Remove original alignment dowel pins from your Toyota bellhousing and
transfer them into the new bellhousing adapter (or purchase and install new
dowel pins).

35. Mount new bellhousing onto front of 5 speed transmission. Attach
bellhousing to transmission using the original Toyota mounting bolts. Apply
thread sealer to the "A" bolts, torque all mounting bolts to 27 ft. lbs.

36. Install shift fork pivot ball supplied with bellhousing into the pivot
ball mounting hole  "A"  machined into the bellhousing, tighten. Position 
shift fork supplied with bellhousing onto	 1/2 shift fork pivot ball. 
Position Downey throw-out bearing #90363-1430 onto the bearing
retainer of the transmission and into the shift fork.

37. With the bellhousing, transmission, and throw-out bearing assembled,
you can now bolt the bellhousing to the engine. Guide the transmission
input shaft through the clutch disc and into the pilot bushing as you guide
the bellhousing onto the engine dowel pins. DO NOT force the assembly
together. Bolt bellhousing to engine.

PREPARING T-350 AUTOMATIC TRANSMISSION

38.TRANSMISSION MODIFICATION

NOTE - Adapters used to adapt a T-350 to the 1979-83 and 1984-newer
transfer-cases are manufactured by Downey and their installation
instructions are below. Adapters used to adapt an AW4 Toyota Automatic or
TH7OOR-4 GM Automatic are manufactured by Advanced Adapters and they
include their own separate instruction sheets.

o '79-83 Turbo 350- It will be necessary to have Downey's output shaft
installed into your transmission. Any transmission shop can do this
installation for $80.00 to $100.00.

o '84-newer Turbo 350 - Your transmission output shaft is approximately
6" long with the rear extension housing removed. Using a good hacksaw or
abrasive cut-off saw, shorten the shaft to 3.720" long from the rear of the
case. After cutting, deburr splines with a file.

o Converter Lockup - If you are using a 1981-91 T-350 or 1982-89 TH7OOR-4
transmission and lockup torque converter (normally used with computer
operated engines) you must use a special B&M torque converter lockup switch
(Downey #32100-80217). This switch is necessary for use with Carburated or
TBI/TPI engine conversions. It provides a manual lockup with an over-ride
for automatic high gear lockup. This switch includes its own installation
instruction sheet.

MOUNTING T-350 AUTOMATIC TRANSMISSION TO ENGINE

NOTE - Steps 39 and 40 are not necessary if you have purchased a complete
GM engine and transmission assembled as one piece.

39. FLYWHEEL

o Buick 231 - Install the appropriate flywheel (flexplate) GM #1257041 onto
crankshaft using special GM mounting bolts and torque specs.

o Chevy V-6 or V-8 - Install the appropriate GM flywheel (flexplate) onto
crankshaft using special GM mounting bolts and torque specs. Your flywheel
choice will depend upon whether you are using a 1985-older internally
balanced engine, or a 1986-newer externally balanced engine. Your local
Chevy dealer can assist you with selecting the correct flywheel.

40. TORQUE CONVERTER

o Before bolting transmission to engine, mount torque converter onto
transmission input shaft. Be sure both sets of torque converter female
splines are engaged onto input shaft male splines, and be sure torque
converter is properly and fully seated. NOTE -Torque converter must slip
onto two sets of splines, then one set of tangs. If the torque converter is
properly installed and seated, it should need to be moved forward
approximately 1/4" to contact flywheel after transmission is bolted to
engine. If this is not the case, STOP and be sure torque converter is fully
seated. Bolt transmission to engine.

o Pull torque converter forward and align bolt pattern with flywheel bolt
pattern. Flywheel can be turned a few teeth at a time to achieve bolt
pattern alignment by inserting a large straight slot screwdriver into a
flywheel tooth and pivoting or leveraging against the transmission case.
After bolting torque converter to flywheel, install the proper lower torque
converter inspection cover (not included) for the transmission you are using.

ADAPTING T-350 TRANSMISSION TO TRANSFER CASE

41. Remove transfer-case from stock transmission, then remove front housing
from transfer-case. This is the forward section which mounts transmission
shifter and/or transfer-case shifter (depending upon year model).

'79-83 Models Only
a. Install new oil seal into bearing retainer portion of the adapter (if
not previously installed) with oil seal spring facing transfer-case oil.
Install this portion of the adapter onto the transfer-case using the
supplied gasket and non-hardening gasket adhesive. Two metric bolts have
been supplied for the two top holes on the adapter plate. The remaining
holes use the stock bolts.

b. Install transmission portion of adapter onto T-350 transmission using a
GM 0-ring and/or silicone sealant. Install provided allen head bolts and
tighten.

c. Bolt both sections of adapter together with provided 1/2" bolts using
silicone sealant or non-hardening form-a-gasket adhesive between the
surfaces, especially near alignment ring surface. Engine, transmission! and
transfer-case are now one piece ready to hoist into engine compartment.

'84-newer Models Only

a. If you have not removed plastic speedo drive gear from the transmission
output shaft, compress spring clip, remove and discard speedo drive gear.
Do not discard spring clip.

b. Install new drive hub onto shortened T-35O output shaft, and install
speedo drive gear spring clip.

c. Some transfer-cases have a small bearing retainer clip locking in the
upper and lower front bearings. The clip must be removed and discarded.

d. Install adapter onto front of transfer-case using supplied gasket and
your stock bolts. NOTE -The oil seal has been pre-installed by Downey. The
exact depth of the oil seal into the adapter is important, do not tamper
with the oil seal location.

e. Install transfer-case and adapter onto back of T-350 transmission using
a GM 0-ring and/or silicone sealant. It will be necessary to align the
transfer-case input shaft male splines into the drive hub female splines
while seating the adapter up to the transmission. Install provided allen
head bolts and tighten.

f. Some transfer-case shift levers mount onto top of transfer-case (Figure
A), and others mount onto the spacer plate between transmission and
transfer-case (Figure 3). If yours mounts like figure A, you must fabricate
a block-off plate for the Downey adapter. The block-off plate can be
fabricated from steel or aluminum plate. Apply silicone sealant and
tighten. If yours mounts like figure B, simply remount the 4WD shift lever
into the Downey adapter after the engine is installed. Engine,
transmission, and transfer case are now one piece ready to hoist into the
engine compartment.

Chevy V-6 or V-8
If you are using Slick Fit Headers instead of exhaust
manifolds, mount headers onto engine. There should be a slight clearance
problem between the headers and bellhousing. Grind bellhousing flange until
adequate clearance has been achieved. Remove headers.

ENGINE INSTALLATION

42. Before installing engine:

o Remove transfer-case mounting crossmember from frame.
o Remove starter from engine.
o Remove automatic transmission dip stick and tube.

NOTE - You may opt to jump ahead to the alternator, power steering, and air
conditioning instructions at this point, however engine positioning will be
simplified, and you will not damage engine accessories if you install them
after the engine is installed.

o Chevy V-6 or V-8 - On 79-85 models, torch original front motor mounting
brackets oft the frame. Grind the torched area smooth.

43. Hoist engine into engine compartment. Your best hoisting position will
be a location near the rear of the engine.

44. Using a combination of your engine hoist and a floor jack, bolt the
stock transfer-case mounting cushion and crossmember onto the transfer
case. Jack crossmember up to original mounting location against the frame.
Distributor firewall clearance may not allow you to align crossmember with
its original mounting location. If this is the case, don't panic. proceed
to step #45.

45. MOTOR MOUNTS

While floor jack holds rear crossmember against the frame, install front
motor mounts.

o Buick 231 - with stock front cushions attached to Downey's engine mounts
finger tight, lower engine until stock cushions rest on stock frame mounts.
Bolt and completely tighten stock cushions to frame and engine mounts.
Align, bolt, and completely tighten rear crossmember to frame.

o 79-85 Chevy V-6 or V-8 - These particular conversions are the toughest
because there is not a specific engine position. Before determining exact
motor mounting position, you must ensure there is adequate clearance
between distributor and firewall. Your goal should be to retain a stock
transfer-case location, eliminating the need for drive shaft modifications.
Use of a body lift kit will provide additional distributor clearance and
can eliminate drive shaft modifications in some cases if the firewall is
dented. The firewall can NOT be dented when NOT using a body lift kit
because the heater core is mounted immediately inside the firewall. V-8
conversions in '79-83 models will be the toughest because the transfer-case
must be positioned significantly rearward, and/or the V-8 radiator must be
positioned significantly forward of the stock location.

With engine mounts tight against engine block, attach weld-on frame
brackets (gusseted "L" brackets) to engine mounts using the 1/2" bolts and
cushions supplied. Move engine forward until distributor firewall clearance
has been achieved, then temporarily clamp transfer-case crossmember to
frame. Raise or lower engine until level front to rear, side to side. Clamp
weld-on frame brackets to frame. Before welding, ensure there is adequate
clearance for distributor removal, then inspect all other clearances.
IMPORTANT - Before committing to a weld-in engine position, read the
remainder of this manual if you have not already done so. You will see why
engine position is critical, especially concerning radiator and fan clearance.

Weld frame brackets to frames. Tighten 1/2" bolts between engine brackets,
cushions and frame brackets. With front motor mounts secure, block
transmission in its present position to allow rear motor mounting
crossmember removal. Unbolt transfer-case motor mount cushion from
crossmember, lower crossmember. Align and bolt crossmember to its original
frame location. It will now be your responsibility to fabricate any adapter
bracket necessary between the crossmember and cushion. Using floor jack,
remove blocks and completely tighten all crossmember and cushion mounting
bolts.

o 86- Newer Chevy V-6 or V-8 - Your stock cushions must be removed from the
frame and GM cushions attached to the engine at this point (refer to
instruction #26). Attach new bolt-on frame brackets onto the original frame
brackets and tighten. Lower engine while aligning engine cushions with
bolt-on fame brackets. Install mounting bolts and tighten. On all
conversions using a T-350 transmission, bolt the rear crossmember to the
frame and tighten all crossmember and rear cushion mounting bolts. On V-6
conversions using the 5 speed transmission, it will be necessary to
elongate the crossmember mounting holes by approximately 3/8". Block the
transmission to allow crossmember removal. After elongating, bolt rear
crossmember to the frame and tighten all crossmember and rear cushion
mounting bolts. NOTE - The 1986-newer Chevy Vortec V-6 bolt-on frame
brackets have a double bolt patters at 1 1/8 hole centers. One set of bolt
holes will position the engine forward to eliminate drive shaft
modifications, at the expense of reducing fan blade clearance. The other
bolt holes will position the engine rearward 1 1/8~ to allow additional fan
blade clearance while requiring drive shaft modifications. You can use
either choice you prefer.

46. Engine, transmission, and transfer-case should now be completely motor
mounted, front and rear. Check all motor mount and cushion bolts for
adequate tightness, front and rear. Remove engine hoist and floor jack.

47. STARTER

o Buick 231 - Install starter GM #109063 using special starter mounting bolts
GM #1366042 and #1366043 (one each).

o Chevy V-6 or V-8 - Starter must be compatible with the flywheel or
flexplate you are using. Your GM dealer can provide the correct starter
part number needed based upon your engine and the GM flywheel part number
being used.

CONVERSION COMPLETION

Some of the following steps are not specific. There will be many variables
due to various engines, transmissions, ignition systems1 fans, shrouds, etc.

48. ALTERNATOR MOUNTING

o  Buick 231
a. Transfer the stock lower alternator mounting bracket onto the left front
(driver's side) motor mount. If yours is the three bolt mounting bracket,
simply bolt it onto the motor mount. If yours is a four bolt mounting
bracket, you must cut along the dotted line as illustrated, to eliminate
the founth mounting hole, then bolt bracket onto the motor mount.

b.Install provided idler pulley onto provided water pump casting in the
lower slotted hole of the water pump casting (Downey #122511-R). If your
vehicle has air conditioning, the idler pulley will be used to tighten the
air conditioning belt. If your vehicle has power steering and no air
conditioning, the idler pulley is not necessary and the slotted hole in the
water pump casting can be ignored. If your vehicle has neither power
steering nor air conditioning, the idler pulley is necessary to tighten the
belt between crank shaft pulley and water pump pulley as illustrated.

c. Install water pump casting and idler pulley onto left (driver's side) of
V-6 water pump using the three 5116" X 5" long bolts supplied. It aligns
with a triple bolt pattern on the pump. NOTE - Check the V-6 water pump and
Downey water pump casting for flatness to insure that the casting does not
rock or lean when tightened. Correct by filing one or the other. WARNING -
Should the need ever arise to replace a water pump casting bolt, do not use
a bolt in excess of 5" long. A longer bolt could crack the cylinder wall.

d. Install alternator onto lower alternator mounting bracket using the
stock mounting bolts. Install new belt tightening bracket between water 
pump casting and alternator as illustrated. Downey's Buick 231 kit requires 
use of the following components (not supplied):
	GM #25503832 crank balancer
	GM #25522581 crank pulley
	GM #25522583 fan pulley
	Dayco #15310 '79-84 alternator belt
	Dayco #15335 '85-newer alternator belt
	Dayco #16345 water pump belt (non power steering)

o Chevy V-6 or V-8 - Mounting brackets are not presently available for
retaining the Toyota alternator on these conversions. You must use a GM
alternator with internal regulator, and GM mounting brackets GM #14081227,
#14015533, and #6262934.

49. POWER STEERING MOUNTING

o Buick 231

a. '79-80 vehicle owners must obtain a 1981 or newer Toyota Pickup power
steering pump.

b. Remove power steering pump from all stock mounting brackets.

c. Remove stock pulley from power steering pump.

d. Mount power steering pump onto the new pump mounting casting. Secure
pump to casting using provided lOmm X 3Omm bolt in the top hole and lOmm X
35mm bolt in the bottom hole.

e. Attach pump and pump mounting casting onto left (driver's side) cylinder
head using standard 3/8" bolts and flat washers. Slotted holes in the
casting align with threaded holes in the cylinder head.

f. Attach the new belt tightening bracket onto the pump using provided lOmm
X 2Omm bolts.

9. Align belt tightening bracket into slot on the water pump casting and
secure with provided lOmm X 2Omm bolt,

h. Install new pulley onto power steering pump. Deep recess side of pulley
should face pump. The new belt required should be 45" long, Dayco #15450.

o Chevy V-6 or V-8 - Mounting brackets are not available for retaining the
Toyota power steering pump on these conversions. Install the appropriate GM
pump and pump mounting brackets for the engine you are using. Use Downey
hose adapter #4441 1-MPF to attach an American female thread hose to the
pressure hose side of the Toyota power steering gear box.

50. AIR CONDITIONING MOUNTING

o Buick 231

a. There are three compressor styles used on Toyota Pickups and 4 Runners.
the '79-83 Pickup compressor, '84-newer Pickup compressor, and '84-newer 4
Runner compressor. If you are doing a '79-83 Pickup, or any 4 Runner
conversion, you must obtain an '84-newer Pickup compressor.

b. '84-newer compressor only - Attach Downey compressor mounting bracket
(#88431-R84V6) to front of right (passengers side) cylinder head using 3/8"
bolts supplied. Attach compressor to mounting bracket using the 8mm X lOOmm
bolts supplied. Attach the upper brace and support bracket to the
compressor and water pump as illustrated. This mounting configuration
requires use of Gates belt #7470.

o Chevy V-6 or V-8 - Mounting brackets are not available for retaining the Toyota 
compressor on these conversions. leaving you with two choices:

a. You can fabricate mounting brackets to allow use of the Toyota
compressor, then stock hoses can be used. NOTE - We have seen a Toyota air
conditioning compressor adapted to a Chevy Vortec V-6 engine using
home-made mounting brackets and a Ford Tempo serpentine compressor pulley.
We have been told the Tempo pulley is a direct bolt-on onto the Toyota
compressor, but this is NOT first hand Downey information at this time.

b. You can use a GM compressor and GM compressor mounting brackets. They
will provide the correct pulley and belt alignment, but custom hoses or
splicing will be required. This service can be supplied by most air
conditioning shops.

51. RADIATOR MODIFICATIONS

o Buick 231 or Chevy V-6 - Downey #16400-R is a larger 3 core bolt-in
radiator that has a built-in automatic transmission cooler. If you do not
use the Downey radiator, you must have your stock radiator modified:

a. You must have the two small cores replaced with 3 larger cores (at least
35 gallons per minute).

b. The upper and lower hose fillings must be reversed (right to left, left
to right).

c. If using an automatic transmission, you must purchase an aftermarket
transmission cooler for placement in front of the radiator. Coolers are
available from parts stores and speed shops, exact size and shape is not
critical. You will need approximately 12' of internally braided cooler hose.

d. Your radiator hoses should be 1 1/2 " l.D., the upper 20" long (Gates
#264400 universal flex with formed elbow is ideal), the lower 20" long
universal flex.

e. It is sometimes necessary to use rubber radiator hose bushings between
Downey's radiator and your locally obtained radiator hoses. This situation
is normal since there are so many radiator fitting sizes on various
radiators, and hose manufacturers must offer multiple hose sizes. Rubber
hose bushings are readily available in all sizes in your home town.

f. The stock fan shroud should be modified and retained if possible.

0 Chevy V-8 - Downey #16400-RV8 is a large 4 core radiator that has a
built-in automatic transmission cooler. These conversions normally require
significant modifications to the front radiator mounting panel and upper
tie bar. We are not in agreement with those who believe the following
modifications are only required on '79-83 models:

a. You must cut the upper tie bar (aborting hood latch) and cut as much
sheet metal as necessary for radiator mounting. You must fabricate mounting
brackets to position the V-S radiator 1" to 2" forward of the stock
mounting location, closer to plastic grille panel. (See suggested tie bar
configuration at right).

b. The front crossmember (directly below the radiator) will probably
require modification to allow use of the V-8 radiator.

c. You will probably have to convert to pull-pin type hood latches.

d. The stock fan shroud should be modified and retained if possible.
Assuming a conventional fan will not provide adequate cooling for V-8
conversions, it will be necessary to convert to electric fans.

52. FANS

o Buick 231 or Vortec V-6 - Several different fan blades work perfectly on
V-6 conversions ranging from 14 1/2" to 16", flexible or rigid. We have found
that rigid fans cool better than flex fans, however the exact choice of fan
and shroud has been left up to the installer. If your vehicle has air
conditioning, we recommend a genuine GM rigid fan that was made for air
conditioned vehicles. These fans are small diameter for compressor pulley
clearance, and have multiple heavy pitched blades. Fan spacers may be
required for compressor pulley clearance. Universal fan spacers are
available from most parts stores.

o Chevy V-8 - These conversions usually require electric fans due to space
limitations. when using an electric fan it is necessary to obtain one with
adequate CFM for your engine. Most V-S engines require 950 CFM. You may
find it necessary to use two 12" electric fans.

o Reverse Rotation Fans - If you are installing a late model GM engine that
has a single serpentine fan belt, and the single belt drives the water pump
pulley on the back side of the belt (flat side), you have a reverse
rotation water pump and fan blade.

o If you want to convert to a conventional V-belt drive (to eliminate air
conditioning, power steering, or idler pulleys from your GM engine) you
must convert all pulleys to V-belt type, then use a standard rotation water
pump and fan blade.

o If you are going to retain the single serpentine belt system with reverse
rotation water pump, but you do not have adequate clearance for the stock
reverse rotation fan, you must convert to one of Downey's reverse rotation
flex fans.

53. THERMOSTAT 
Some GM engines are equipped with 220 degree thermostats. These
thermostats are compatible with the emission control system, however they
do not allow the engine to run cooler than 220 degrees. If you encounter
overheating problems, you may opt to use a 160 or 180 degree thermostat.

54. DRIVE SHAFTS
Reinstall both drive shafts using the original mounting
bolts. If a conversion has been done that required only slight
transfer-case relocation (less than 1/2"). you might avoid major drive
shaft modifications by simply shortening the male splines on the drive
shaft slip-yoke. You must ensure the slip-yoke will not bottom-out when the
suspension is bottomed-out. If a conversion has been done that required
significant transfer-case repositioning (more the 112"), have your drive
shafts modified at a qualified drive shaft shop.

55. SPEEDOMETER CABLE and VSS
Reconnect speedometer cable and 4WD indicator light wire to transfer-case. 
If using the Downey supplied Vehicle Speed Sensor with a TBI/TPI engine, 
install the VSS at this point, then refer to wiring instructions later in 
these instructions.

56. THROTTLE CABLE
Reconnect. The stock cable is ideal, but you will have
to fabricate your own clamping bracket. The design you choose will depend
on the carburetor and intake manifold you are using (see Downey #78184-F
and #78154-11069)..

57.VACUUM HOSES
You must obtain the necessary fining for attaching vacuum hoses from both 
the brake booster and automatic transmission into the intake manifold. If 
your manifold has only one provision for a fitting, your fitting must be a 
"T" since vacuum is requires for both brake and transmission.

58.MANIFOLDS or HEADERS
Before Installing exhaust manifolds or headers, see Downey catalog for Header
applications.

o Buick 231 Exhaust Manifolds - The left hand (driver's side) exhaust
manifold is generally not a problem, but a 1984 Olds. Cutlass Supreme
manifold offers very good frame clearance. The right hand (passenger's
side) exhaust manifold normally presents more clearance problems. A 1978
Buick Skyhawk manifold GM #1259128 will supply ample frame clearance.

o Exhaust System Routing - When having an exhaust system installed, keep in
mind that you may want to install an auxiliary tank in the future. With
this in mind, your exhaust system should hug the left (driver's side) frame
and exit in the stock location.

59. HEATER HOSES
When installing heater hoses it will probably be necessary to purchase a few 
feet of 5/8" universal heater hose from your local parts store.

60. SHIFT LEVERS
Reinstall shift levers. The choice of automatic shift linkage is entirely up 
to your taste and/or budget. Both Hurst and B&M offer numerous choices at
numerous price levels. We recommend a cable type shifter that requires very 
little mounting space on your floor (see Downey #33121-RA).


WARNING
when mounting the automatic transmission shifter of your choice, ensure
that no part of the shifter apparatus can come into contact with the
transmission or transfer-case during the entire travel cycle of the
apparatus. Move the shift lever through all gears to ensure adequate
clearance. Failure to do so can result in the transmission accidentally
shifting from neutral to reverse because the safety, lock or neutral safety
switch fails to function properly.


61. DIP STICK
On V-8 conversions the automatic transmission dip stick tube will need to 
be heated and bent into a configuration that allows firewall clearance. 
After bending, install dip stick and tube.

ELECTRICAL WIRING

62. GROUND STRAPS
Reconnect all ground straps between frame, engine and body.

63. OIL PRESSURE and TEMPERATURE
Connect oil pressure and temperature wires to the sending units previously 
transferred into your engine.

64. ALTERNATOR

o Buick 231 - Reconnect stock wires to stock alternator.

o Chevy V-6 or V-8 - Remove wires from the stock alternator and/or
regulator if not previously removed. The large 10 gauge wire will need to
be extended to large post on the GM alternator. Next, determine which of
the small wires is hot when the ignition switch is on. This wire must be
extended to reach the #1 terminal on the GM alternator. Next, install a
jumper wire between the 10 gauge terminal and the #2 terminal on the GM
alternator.

65. STARTER
Connect positive battery cable to the larger terminal on the
starter solenoid. Connect the small wire to the inside (closest to engine)
terminal on the solenoid.

66. BATTERY
Install battery, connect positive and negative cables to battery. If you 
have installed a V-8 engine, you might find it necessary to use a higher 
amp hour battery with the required cold cranking power needed for your engine.

67. COIL
You can not use the stock coil or ignition system since they will not be
electronically compatible with your GM distributor. Locate the wire which
was originally attached to the positive post of the stock coil.
This is the hot wire that will feed any GM or aftermarket ignition system
you select. Your need for an external resistor and/or particular coil will
depend upon your choice of distributor. Your GM engine can be equipped with
either a point type or HEI distributor. The large HEI distributor on
even-fire Buick 231 engines will not present a clearance problem since it
is mounted at the front of the engine. The HEI distributor used on Chevy
V-6 or V-8 engines could present firewall clearance problems unless the
firewall is dented. You should not attempt to dent the firewall unless a
body lift kit has been used. We have illustrated two types of ignition
system wiring, the top drawing for conventional point type distributors,
the bottom drawing for the HEI distributor with control unit (amplifier).

68. GM COMPUTER WIRING
We would like to have provided a complete diagram for wiring a GM computer 
(ECU) into your Toyota. This would eliminate the need for a $450.00 custom
wiring harness, ultimately reducing the cost of your conversion by that 
amount. We have been unable to find any two identical ECU wiring 
configurations, so instead of supplying a "complete wiring diagram" we are 
supplying a "generic wiring diagram" (see following page). We have found 
that all ECU's are numbered and color coded ALMOST identically, consequently 
a generic diagram should be sufficient. This means you should find only minor 
or unimportant differences in numbering or color coding between our diagram 
and your ECU. If our generic diagram should prove to be inadequate in 
completing your conversion, you can contract your local GM dealer for the 
exact diagram for your exact ECU.

The last page of this instruction manual provides a generic survey of the
GM computer wiring. This information has been compiled by developing a
composite from six different GM ECU models. You will note we show three
different locations where 12 volts from the battery can be brought into the
ECU, and three different locations where the ECU provides a power output
for an electric fuel pump. Don't let this confuse you, your ECU should
provide only one location for each of these functions. In most cases you
should be dealing with only 5 wires when wiring your ECU.

1. 12 volts from battery to ECU, input.
2. 12 volts from ignition to ECU, input
3. Vehicle Speed Sensor, input.
4. Ground, output.
5. Electric fuel pump, output.

69. VEHICLE SPEED SENSOR WIRING

o If your vehicle is a 1984 or newer Toyota Pickup or 4-Runner equipped
with fuel injection (EFI), you have a vehicle speed sensor (VSS) built
into your speedometer. The stock VSS is compatible with the GM computer
(ECU). Locate the blue/green wire in the stock speedometer wiring loom.
Locate the brown wire coming out of port number 437 of your GM ECU. These
two wires should be connected for VSS operation.

o If your vehicle is not equipped with factory installed fuel injection,
you do not have a VSS, and you must purchase Downey VSS #83710-EFI The
Downey VSS has three wires which must be connect as follows:
Red wire must be spliced into the black/pink wire coming out of port #439
of your GM ECU. The black/pink wire is an input wire that brings 12 volts
from the ignition system to the ECU.

Black wire must be grounded to vehicle body or frame.

o White wire must be connected to the brown wire coming out of port #437 of
your GM ECU. The brown wire is the VSS input wire for the ECU.

o After completing VSS wiring, if the engine will not run, remove the
positive cable from the battery for approximately 15 seconds, reconnect the
positive cable, and restart the engine. This operation will remove bad
input/memory from the ECU that could have been created during wiring.

70. TACHOMETER WIRING
We have two reports that the stock Toyota Tachometer works perfectly fine 
when connected to the GM computer (ECU).
This is NOT first hand Downey information at this time.

71.HOOD
Reinstall hood - Congratulations!

If you would like chrome plated V-6 fender emblems, use GM #1254540 (self
adhesive).