When converting your Toyota 4WD truck to a new engine there are a number of items that you must consider. The information listed in this section covers Toyotas 1979 to 1995. Most areas discussed in this section are categorized by either the year of the vehicle, stock engine that the vehicle was originally equipped with or stock transmission and transfer case.
BODY LIFTS: 1979-85: Although a body lift is not required to complete a conversion on these vehicles, we recommend that you consider a minimum 2” body lift in order to provide additional engine compartment and transmission tunnel area clearances. This will also provide additional clearance for the distributor cap. 1986-95: These vehicles were equipped with an I.F.S. suspension. It is mandatory that your vehicle be equipped with a body lift. A minimum 2” body lift will provide the necessary clearances for the transmission and engine to fit properly. Vehicles without a body lift will require extensive engine compartment modifications. Note: If a T.B.I. block from out of a truck is going to be used, a 3” body lift will be required for hood clearance.
SUSPENSION LIFTS: 1979-85: When performing an engine swap on your Toyota 4WD, we recommend that you install a suspension lift. The suspension lift will be an asset to your vehicle when performing these conversions. It provides your vehicle with better ground clearance and wheel travel. The suspension lift will provide additional clearance between the front driveshaft and starter motor assembly. The installation of a V6 or V8 engine will also add additional weight to the front of your vehicle. For instance, your 4 cylinder engine weighs about 300 pounds. A new V8 engine will weigh in the neighborhood of 575 pounds; and a new V6 approximately 450 pounds. A suspension lift will normally provide the additional support to handle these heavier engines. If a suspension lift is not used on these vehicles, a helper spring or stiffer leaf spring may be required.
1979-81: On these year vehicles, Toyota utilized a front stabilizer bar. This bar attached to the front axle on the driver's side of the vehicle. When installing a V8, the mount where this bar attaches will need to be relocated or removed.
1986-95: When performing an engine swap on your Toyota 4WD with the I.F.S. suspension, we recommend that you install a suspension lift. When positioning a new engine into these vehicles, oil pan clearance is an issue. The easiest way to obtain the proper oil pan clearance is by installing a suspension lift. The suspension lift required for these year vehicles will drop the entire front axle away from the frame, providing the necessary clearances for all engine swaps.
MOTOR MOUNTS: Toyota used a straight axle on 4WDs 1979-85, and started using an independent front suspension (I.F.S.) on 1986 & newer vehicles. We offer motor mounts for various engine blocks. The proper engine mounts will depend on the front axle configuration of your vehicle. The mounts listed for the engines are to be used with both bellhousing and/or transfer case adapters. There are two styles of engine mounts available. The first is the weld-in style that is used on vehicles equipped with a solid front axle. These mounts are fully adjustable and can be either welded or bolted to the inside of the frame rails. By having this adjustable option, you can position the engine so that driveline modifications can be eliminated on certain applications. The two mounts that extend outward from the engine block will usually need shortening in order to fit between the two frame rails. This may vary depending on the height of the engine.
The second style of engine mounts are the ones that bolt onto the existing 4 cylinder or V6 engine pads. These mounts have been designed for an engine location that cannot be varied. This type of motor mount is mandatory on vehicles equipped with the independent front suspension. Motor mounts on these particular installations will normally allow you the ability to adjust the position of the engine correctly up to the original 5 speed tranny or to the popular TH350 & 700R-4 transmission options.
Our weld-in mounts are a complete frame-to-block setup, which includes the rubber insulators. Some of our bolt-in mounts will require the use of a stock GM engine rubber mount (GM# 3990914 or Sealed Power/Federal Mogul# 270-2267 Napa # 602-1106).
Chevy V8: PN3001-S Chevy V8 mounts to Toyota 1979-85 (weld-in) PN713013 - Chevy V8 mounts to Toyota 1986-95 replacing a 4 cyl. (bolt-in) * PN713125 - Chevy V8 mounts to Toyota 1988-95 replacing a V6 (bolt-in) 713125-C CROSSMEMBER MOUNT RELOCATION
Chevy 4.3 V6: TC support PN713001-S Chevy 4.3 V6 mounts to Toyota 1979-85 (weld-in) mount tabs that need to be cut on stock mounts PN713013 - Chevy 4.3 V6 mounts to Toyota 1986-95 replacing a 4 cyl. (bolt-in) Pass. Side V6 mount * PN713126 - Chevy 4.3 V6 mounts to Toyota 1988-95 replacing a V6 (bolt-in)
Buick V6: PN713011 - Buick V6 mounts to Toyota 1979-85 (weld-in) Ford V8: PN713002-S Ford V8 mounts to Toyota 1979-85 (weld-in) PN713016 - Ford V8 mounts to Toyota 1986-95 replacing a 4 cyl. (bolt-in) Pass. Side Ford header and 713016 mount (No mount is available when replacing a stock V6)
*These mount kits provide new GM rubber mounts and a crossmember relocation plate. Driveline modifications will be required.
RADIATORS: A new radiator is normally required when doing an engine swap. We offer a new high efficiency 4-core copper/brass radiator for the Chevy 4.3 V6 & V8 and a Rad-A-Kool 1-core aluminum radiator for Chevy V6 and V8s. These radiators are all a down-flow, core configuration and have the proper inlet & outlet location for these blocks. They come complete with a transmission cooler.
The Rad-A-Kool aluminum 1 core fits vehicles 1979-95, and is rated to cool engines up to 300 horsepower. This radiator is ideal for engine conversions that are tight on space and is your best choice on 1986-95 Toyotas using our bolt-in engine mounts.
Our 4 core copper/brass radiator, designed with 1/2” tubes on 3/8” centers. It is designed specifically for vehicles 1985 & newer. This radiator bolts into the factory location and extends 5” lower than stock. Since these radiators hang 5” lower than stock, you may want to fabricate a steel guard to protect your radiator. Angle iron provides a great solution to protect this lower portion. The original fan shroud should be retained but will require modifications. If you attempt to use this radiator on vehicles 1979-84, you will require modifications to the front crossmember core support. NOTE: These radiators will not work with LT1 blocks. PN716681 - Chevy V6 & V8 radiator (4-core) (Radiator measures 3” thick, 24.25” tall, 24” wide) V8 Upper and Lower Hose - #Universal 1-1/2” Flex hose
PN716698-AA - Chevy V6 & V8 1 core radiator w/ trans cooler (shown right) PN716698-AB - Chevy V6 & V8 1 core radiator w/ out trans cooler PN716698A-LS / P/N 716698M-LS - Chevy LS1 auto & manual single core radiator PN716698A-LT / P/N 716698M-LT - Chevy LT1 auto & manual single core radiator (Radiator measures 3” thick, 22.25” tall, 24” wide)
FAN: On most conversions, you will be able to use a 16" conventional fan. When using a conventional fan, you will be limited on radiator clearance. To obtain additional clearance for the radiator, a short-style water pump could be used. Some of the newer blocks with the Serpentine belt system will usually allow enough radiator clearance to retain a conventional fan. Whenever a conventional fan is used, make sure you have adequate clearance for your radiator and proper shrouding for both airflow & personal protection.
When your engine position does not allow adequate clearance for a conventional fan, an electric fan is an ideal option. An electric fan can either be mounted in front or behind the radiator to maximize on space. Many manufacturers of electric fans offer slim designed fans to aid in this regard. We offer Spal fans which are a high performance, curved bladed pusher or puller. These 16” fans are 16.3” tall, 15.75” wide, and 3.39” deep at the fan motor. The fans are rated at 2070 CFM; and being that they are pre-shrouded, they are ideal for cooling larger engines. Our fan kits come complete with the needed wiring harness which is compatible with both positive and negative ground vehicles. The 3/8” pipe thread sending unit is designed to turn the fan on at 185 degrees and off at 170 degrees. The kit comes with a 40 amp relay, a fuse holder, and all other necessary hardware. In addition, our kit also includes mounting brackets for the fan to the radiator. The mounting brackets are designed for our aluminum radiators; however, we can supply you with brackets to fit our copper/brass radiators upon request. fan-rad clear 2 short pump clear PN716670 - Puller Fan Kit PN716671 - Pusher Fan Kit
OIL PANS: On Toyota vehicles 1979-85 (equipped with the solid front axle), you will be able to use the stock engine oil pan without modifications. On 1986 & newer vehicles with the I.F.S. front axles, you have one of two options. The first option is to equip your vehicle with the recommended suspension lift, providing the necessary stock oil pan clearance. The second option would be to modify your stock pan. The entire bottom of the pan needs to be re-fabricated to fit and some grinding may be required on the front differential housing. You will also notice that there is limited clearance between the pan and differential. Even though clearance is limited, there should not be a concern in this area because both the engine & front axle mounts have very little movement. We did offer modified pans for several years, however, we no long offer this product.
NOTE: Newer GM blocks equipped with the aluminum oil pan should not be used on vehicles that do not have a suspension lift. Modified oil pans are not available for these engines. Starter clearance with the oil pan can also be an issue with these blocks.
OIL FILTER: The original Chevy V6 or V8 oil filter can be retained. On some installations, we have had customers use a remote oil filter adapter in order to provide additional clearance for their exhaust system on the driver's side.
Since the oil filter connection on a Ford block protrudes towards the driver’s side frame rail, a remote oil filter adapter is required. We offer a remote filter adapter, P/N 716084, that provides the oil line connections at a 90 degree angle. This type of adapter provides the greatest amount of clearance for the Ford block.
EXHAUST HEADERS / STOCK MANIFOLDS: On most conversions, you will have the option of using a custom exhaust header or stock manifold. If headers are to be used, you will need to verify your State’s emission requirements since the headers we supply are not smog legal. The following conversion headers are for V6 & V8 blocks. Our headers are designed around conversions using our motor mounts. Due to vehicle variations, some modifications may be required when using our exhaust header systems. These headers are available in chrome or Non-plated (NP). PN717011 - Chevy V8 center dump headers (vehicles 1979-85 only) (Only sole in Stainless, Ceramic coated and Non-plated) TH350 Mods for exhaust clearance V6 HEADER WITH MANUAL TRANS 717056 tight fit 717054 PASSENGER SIDE * PN717053 - Chevy V8 rear dump manifold style headers (for vehicles replacing a stock V6) * PN717054 - Chevy V8 rear dump manifold style headers (for vehicles replacing a 4 cylinder) PN717056 - Chevy 4.3 V6 headers (vehicles 1979 & up) (Manual trannys require clutch arm mods.) * PN717041 - Buick V6 headers (vehicles 1979 & up) PN717012 - Ford V8 center dump headers (vehicles 1979-85 only) * PN717044 - Ford V8 rear dump manifold style headers (vehicles 1979 & up) *Headers will have interference problems with the release arm when used with a manual transmission.
Smog legal vehicles will normally require you to retain the stock manifolds. On GM V8 installations, the stock manifolds from a 1982 & newer low performance car engine work the best. These manifolds can normally be installed without any modifications. For Chevy V6 installations, the manifolds from a 1985 Chevy full size truck are an option. You can also try manifolds off of a 1980 Monte Carlo equipped with a 3.8 V6. On Ford V8 conversions, the early Maverick manifolds work well; however, they do not have smog connections. We have been told that the exhaust manifolds from a V8 Ford Explorer will fit with only minor modifications required. On the Buick V6, manifold #25507801 and #1250528 should be used.
NOTE: All of the stock manifolds suggested above were obtained from customers that have completed the various conversions. We have not personally verified the fit of these manifolds into these Toyota conversions. manifold PS manifold DS TOY TRK SMOG LEGAL DRIVE SIDE 1990 TOY TRK, CALIF SMOG LEGAL PASS SIDE MANIFOLD
FUEL PUMP: A carbureted block can have fuel supplied to the new engine in two ways: an electric fuel pump or a mechanical fuel pump. The mechanical pump is normally part of the engine and, at times, does create some clearance problems. When a mechanical pump cannot be used, the alternative is an electric pump. Most carbureted blocks require a fuel pressure rating of 5 to 7 PSI.
Fuel injected blocks require a higher fuel pressure. These blocks can use the stock fuel pump that your vehicle was equipped with, provided it has the correct PSI rating to match your engine. If this is not an option, you can install an in-line fuel pump with the correct PSI rating to match your block. This pump should be added slightly ahead of the fuel tank. When using an aftermarket electric fuel pump, you should also incorporate a safety circuit to turn off the fuel pump if the engine were to stall.
Whether your new engine is carbureted or fuel injected, and you use either a mechanical or aftermarket electric fuel pump, the stock fuel pump located in the fuel tank should not have to be removed.
ALTERNATOR: When replacing a 4 cylinder or V6 engine, we recommend that you purchase a new V8 alternator with an internal regulator to provide better charging to your electrical system. When wiring the new alternator, you must remove the original Toyota regulator. GM Alternator Bracket GM #14081227 (Adjuster) GM Alternator Bracket GM #14015533 (Front Bracket) GM Alternator Bracket GM #6262934 (Spacer) If you elect to use the GM alternator that is equipped with a built in regulator, you will need to change the wiring. Remove the existing Toyota regulator and cut the wires that feed the regulator. These wires will be the source of power to your new GM alternator. The large 10 gauge will need to be extended to the large post on the back side of the new alternator. You will then need to determine which of the small wires is hot when the ignition switch is on. The hot wire will then need to be extended to reach the number 1 terminal on the GM alternator. You must then install a jumper wire between the 10 gauge terminal and the number 2 terminal. Use the original GM plugs to make sure the connections are properly fitted.
PULLEY SYSTEM: The belt system required to drive the alternator, water pump, power steering, and air conditioning can all be accomplished with a two belt system. If a three belt design is attempted, you will find that the length is too critical for radiator clearances. With the two belt system, you will be able to drive the alternator, water pump, and crank on one; the air conditioning, water pump, and crank on the other. Make sure that the air conditioning and alternator brackets are adjustable. The Serpentine belt system found on newer motors also works excellent.
WATER PUMPS & THERMOSTATS: Chevy engine installations have the option of either a long or short water pump. The long style water pump is most commonly used on Chevy blocks. The stock bracketry on most V6 & V8s is designed to be used with a long style water pump. A short water pump will give additional radiator clearance; however, accessory brackets are sometimes hard to come by. We offer a high performance brand of water pumps and thermostats for Chevy V6 & V8 conversions.
On Chevy & Ford blocks with a Serpentine belt system, these blocks can usually retain this stock belt system. They will normally provide sufficient clearance for your radiator. Be careful if you replace the water pump on a Serpentine system since they usually rotate in the opposite direction.
POWER STEERING: You can utilize your original stock power steering pump by fabricating a mounting bracket to fit your new block. The original hoses can usually be retained without modifications if the stock pump is retained with a custom fabricated bracket. However, we recommend utilizing a stock power steering pump and bracket from the engine that you are installing.
For example: When installing a Chevy V8, you would use a standard GM power steering pump. The only modification needed would be to couple the GM pump to the Toyota box. This can be accomplished by having a custom power steering hose made in which one end is a Chevy fitting to fit the pump, and the opposite end is equipped with a fitting for the Toyota box. This installation would only require one custom hose - which is the pressure hose. The return line is simply a rubber hose with steel fittings couple together with hose clamps. This same procedure will work for Chevy V6, Buick V6, and Ford V8 installations.
AIR CONDITIONING: Toyota used three different types of air conditioning compressors. Each type of compressor will require a custom bracket to be made for your new engine. We recommend that the compressor be located on the passenger side so that the original A/C lines can be retained without modifications. If you don’t want to fabricate your own brackets, a simpler way is to retain the air conditioning compressor on the new engine. The stock Toyota air conditioning lines can be spliced to the new engine A/C lines very easily. Check with your local automotive parts store for an A/C splice kit. This eliminates any requirement for custom compressor bracketry.
FLYWHEELS & STARTER MOTORS: The starter motor must match the flywheel that you have on your engine. GM engines: You will be able to use either a 153 tooth & 168 tooth flexplate. Buick engines: On both automatic and manual applications, you will be limited to a 160 tooth flywheel/flexplate. Ford engines: On Ford blocks, you will be able to use either a 157 tooth or 164 tooth flywheel/flexplate.
Depending on your application, it is critical that you properly match the starter and the flywheel. On Ford applications in particular, the bellhousing must also be matched. For GM applications using a 168 tooth flywheel, use starter #3510 or GM# 1108400. For GM applications using a 153 tooth flywheel, use starter #3631 or GM# 1108789. These starters can sometime cause exhaust clearance problems. For a trouble free application, a gear reduction starter is ideal because of its size. For Buick applications, use Delco# 1968122; and on Ford applications, the standard starter to match your bellhousing and flywheel will work fine.
GAUGES: When converting to a V6 or V8, you must use the stock sending units. These units will be compatible with your stock Toyota gauges. Since the oil pressure and engine temperature sensors have a metric thread, you will need to use a special bushing in your new manifold for adapting to these metric threads. These items are available from your local automotive parts. Stewart Warner fittings are normally the easiest to work with.
If your vehicle is equipped with a factory tachometer, you will have two options: You can buy an after market tachometer or you can re-calibrate your stock one. When swapping a Chevy or Buick V6 into vehicles that were originally equipped with a V6, no modifications to your tachometer will be required. On Chevy, Ford or Buick engine swaps, your tachometer will run anywhere from 50% and up off of calibration. To re-calibrate your tachometer, a trip to your local electronic store will be necessary. By purchasing a 5K OHM trim potentiometer, you will be able to fine tune your tachometer. The Toyota tachometers accept a pulse ignition signal from the coil and converts it into a proportional DC signal that drives the meter in the dash. By adding the potentiometer in line with the tachometer input wire, you will be able to calibrate it by restricting its impulse signals. A small 10 turn potentiometer is the easiest to use for this calibration procedure.
IGNITION SYSTEM: Once your conversion is complete, you will need to rewire your ignition system. Below, we have listed the two types of ignition systems that you could have used when installing a new engine.
Ignition: Your new engine can be equipped with either a "point-type" or an "HEI" type ignition. These will both fit into your vehicle, with only slight firewall modifications required on the HEI distributors. When using the HEI distributor, the hot wire from the ignition will plug directly into the distributor battery terminal. If you are attempting to install a fuel injected or throttle body motor into your vehicle, then we recommend that you purchase a Toyota Service Manual to help you identify the existing wiring system for compatibility with the new engine.
What you will need to do is locate the yellow wire that was originally attached to the positive side of your stock coil. This is the hot wire that will feed your new GM ignition system. If you are using a point-type distributor, you will need to install an external resistor that is compatible with your new coil and distributor. If you are using an HEI system, this same yellow wire will need to be attached to the electronic control unit which will then attach to the positive side of the ignition coil.
Charging System: The power source for your vehicle is referred to as the charging system. It is imperative that you have this system wired correctly so that your battery will be recharged, and you will be able to operate all of your electronic accessories. Since you are replacing a 4 cylinder engine and installing a V6 or V8 engine, you will need to install a new battery with the required cold cranking power needed for your engine. A typical V8 requires a rating no lower than 550 amps. If you are using your stock alternator along with a new starter, your stock wires will simply attach to the new starter. NOTE: When using a V8, you should use at least a 90-100 amp alternator. Your alternator will already be wired correctly. However, if you are installing a new GM alternator, you will need to locate the correct wires for supplying the power to the new alternator.
WIRING: When it comes to computer controlled engine blocks, there are many aftermarket sources. We have listed two sources that manufacture conversion wiring harnesses: Howell Engineering (810) 765-5100 G.M. wire harnesses Street & Performance (501) 394-5711 G.M. & Ford wire harnesses Speed Scene Wiring (210) 651-1894/1895 G.M. wire harnesses