2. Engine Swap General Info

ENGINE/MOTOR MOUNTS: 

2.8 replacements:  The engine mounts that we manufacture have been designed around the use of the original 2.8 V6 rubber engine supports.  The original V6 rubber mounts that are bolted to the chassis must remain in their original position for use with the new V8 engine, 4.3 V6 engine, and Buick V6 engines. 

 

4 cylinder replacement:  For 1982-90 vehicles originally equipped with a 4 cylinder engine, you will need to purchase two of the original 2.8L GM motor mounts.  These mounts bolt into the frame rails replacing the stock 4 cylinder mounts.  These pads must be installed onto your frame before proceeding with your engine installation.  This mount is GM Part No. 22188284 or MT2436 (two are needed).

 

When you install the GM frame mounts on vehicles 1985 & newer, you will have tapped holes that will make the installation of the new mounts very easy.  On vehicles that do not have these tapped holes, you will need to install the mounts from the bottom side of the chassis.  This will require the disassembly of the "A"-arm assembly and will take approximately 6 hours.  An alternative would be to simply cut a small access hole on the backside of the crossmember to provide clearance for both a wrench and nut enabling you to secure the mounts in the proper location.  Once the 2.8L mounts are installed, the conversion mounts that we manufacture will then position the V8 engine.

 

4.3 replacements:  For vehicles that were originally equipped with a 4.3 V6, we offer a set of motor mounts that utilizes the stock V6 mount assembly allowing the installation of a Chevy V8.  These mounts use the 4.3 rubber mount and then a 5/16” plate mount to allow for the offset of the V8 engine. 

 

4 cylinder replacement:  For 1991-2000 vehicles originally equipped with a 4 cylinder engine, you will need to purchase two of the original 4.3L GM motor mounts.  These mounts bolt into the frame rails replacing the stock 4 cylinder mounts.  These pads must be installed onto your frame before proceeding with your engine installation.  This mount is GM Part No. 22188970 or MT2627 (two are needed).  You will also need to purchase two steel frame perches GM# 15602789 (left steel mount), and GM# 15674856 (right steel mount).  Once the 4.3L mounts are installed, the conversion mounts that we manufacture will then position the V8 engine.

 

TRANSMISSION SELECTION & CONSIDERATIONS:

After selecting your engine, you must now decide on the proper transmission.  The Borg Warner T4 and T5 transmissions are compatible with our bellhousing and are capable of 250 ft/lbs. of torque.  If your vehicle was equipped with the Isuzu M73 transmission, it will need to be replaced.  If you have a 700R-4 overdrive automatic transmission, the transmission case will need to be replaced with that of a full-sized vehicle.  We feel that the best transmission of choice for both the 2WD and 4WD vehicles is the TH350 transmission.  This transmission is durable and easy to install.  Most conversions will require some kind of transmission modification.  We have detailed specific modifications and installation procedures for most of the popular transmission selections in this manual.

 

700R:  We commonly deal with two types of GM 700R transmissions.  The S10/S15 used a 700R up against a 2.8L V6.  This transmission differs in two areas from a 700R that was originally bolted to a V8.  The first difference is the bellhousing bolt pattern.  The 2.8L 700R version is commonly known as the 60 degree bolt pattern, and the 700R V8 version is known as the 90 degree bolt pattern.  The second difference is the 2.8L 700R uses less clutch packs than the V8 700R.

 

If you want to retain your 700R, you will need to switch your 2.8L 700R transmission casing to a V8 700R casing.  (Note:  S10/S15 equipped with a 700R and a 4.3 V6 have the 90 degree bolt pattern which will not need to be changed.)

 

T5:  The T5 equipped in these vehicles are not recommended for bolting up to the Chevy V6 or V8; however, we do carry a bellhousing for customers that wish to retain this transmission on 1984 and newer vehicles.  On 2WD vehicle applications, you should never retain this 5 speed.   On 4WD vehicle applications 1982-83 having a mechanical clutch or manual transmission and used with a 4 cylinder engine, you should consider switching to an automatic transmission due to the cable-operated clutch linkage.

 

NV3500:  This transmission is normally found up against the stock 4.3 V6 and does not require an adapter when converting to the V8. 

 

TH350:  This is the most popular transmission to be installed in combination with a V6 or V8 engine selection.  On 2WD vehicles, a TH350 with a 9” tailhousing can be installed without driveshaft modifications.  On 4WD vehicles, a TH350 replacing the 700R (using our adapter) can be installed without driveshaft modifications.  When replacing a T5, no driveshaft modifications are necessary, but a stock adapter housing and transfer case shifter components are required. 

 

Flywheel, Flexplate & Clutch:  When using an automatic transmission such as the TH350 or the 700R, we recommend the use of the large diameter 168 tooth flexplate.  Make sure the flexplate you select is balanced for the engine that you are using.  Some Chevy engines will require externally balanced flywheels.

 

When using a manual 4 or 5 speed transmission, we have a maximum clutch disc size of 10-1/2".  The pressure plate is a short throw design for use with the new GM slave cylinder.  It is highly recommended that you use this pressure plate.  Failure to do so may result in improper clutch disengagement.  The pressure plate, clutch disc & flywheel assemblies are available through Advance Adapters.  These clutch items are all manufactured by Centerforce Clutches.

 

Transmission Crossmember Modifications:  On 4WD conversions, your transmission crossmember will remain in the stock location.  There may be slight modifications necessary to the two slots that locate the bolts for the transmission crossmember support.  On 2WD conversions using a TH350 transmission, you may be required to modify the mounting area to match the TH350 rubber mount.  There are slight differences between the years, but most applications can be easily modified for use with the new transmission.

 

Transmission Column Shifter:  In order to retain the original automatic transmission column shifter, you will need to make some modifications to the control lever.  The lever will need to be bent back closer to the firewall and the linkage rod will need to be adjusted accordingly.  On 4WD models, a new linkage bracket from a 1989 S10 equipped with a 4.3 V6 will be required. 

 

TRANSFER CASE & AXLE STRENGTH:

The S10/S15 4WDs used either a NP207 or NP231C transfer case.  These transfer cases are chain-driven units and are built strong enough to handle the torque of the 4.3 V6 or V8. NP207 TC

 

The stock S10/S15 axles are adequate to handle most 4.3 V6 & V8 conversions.  Caution should be used on 4WD vehicles running larger tires or conversions with high performance engines.

 

SUSPENSION REQUIREMENTS:  

The installation of a V8 is about 175 lbs. heavier than stock.  On 2WD applications, your front suspension will normally drop about an inch.  We recommend using a heavy duty shock which will compensate for this drop, or you can change to an extended cab front coil spring which has a greater load rating.  With a greater rating, it should raise the vehicle back to its original height.  Some vehicles have encountered severe wheel hop & spring wrap up in the rear axle.  Some solutions for this problem could be to install a set of ladder bars or kicker shocks to help prevent this problem. 

 

On 4WD applications, the suspension is normally equipped to handle the extra weight.  Adjusting the torsion bars will compensate for any drop in front end height.  

 

When converting to a Vortec 4.3 V6 in either a 2WD or 4WD vehicle, we have not noticed any difference in vehicle height.  Therefore, no adjustments are needed to your vehicle’s suspension.  Once completing any one of these vehicles, your front end alignment should be checked.

 

BODY LIFTS:  

A body lift is not required on both the 2WD & 4WD versions.   However, we have found that a body lift greatly increases additional engine, transmission tunnel & hood clearance.  This, therefore, reduces the amount of firewall and floor pan modifications.  Usually a 2” body lift is adequate in helping to alleviate these clearance problems.

 

COOLING REQUIREMENTS:  

The radiators from Advance Adapters are the best possible solution to keeping high performance engines cool.  When replacing a 2.8L or 4 cylinder, a radiator upgrade is normally required.  We offer two choices of aluminum radiators.  We carry a single core with plastic tanks and a custom two core that is branded as (AA).  All of these radiators bolt in the stock location.  On vehicles that were originally equipped with a 4.3L and converting to a V8, we recommend trying your stock radiator first.

 

In order to cool a high performance V8 engine, you should not waste money in trying to modify the existing radiator.  Our radiators will maximize the cooling potential for your new engine conversion.  The Rad-A-Kool radiator, P/N 716694-AA works excellent.  Using modern aluminum core technology, customers can expect a 20 degree temperature drop compared to copper/brass radiators. The dimensions of the Rad-A-Kool radiator are 32" wide, 16-1/2" tall & 3" thick.  These dimensions require you to widen the core support opening.  The transmission cooler lines on both radiators will remain on the passenger side of the vehicle for easy access. 

 

Fan Shroud:  When installing a V6 or V8 engine, it will be necessary for you to modify your stock fan shroud.  The mounting portion of the shroud that holds the radiator in position should be retained for use with your new radiator.  If the upper and lower portions are retained, the new radiator can be easily installed.

 

Electric Fans:  On most conversions, it is a tight fit to retain a stock conventional fan.  A 17” engine-driven fan works well.  We suggest that you consider using two remote electric fans on the outside of the new radiator. We recommend the use of two 10" or 12" Flex-A-Lite pusher fans to assist in achieving the 950 CFM V8 requirements.  These fans must be used on the front side of the radiator.  The 10" can be installed with minor modifications, while the 12" will require major modifications to the grille and radiator support brackets.  It may be necessary to install an aftermarket tubular grill for additional fan clearance.  Flex-A-Lite Model 20 works excellent, but will require special mounting brackets and slight trimming in order to fit on the front side of the radiator. dual fans

 

Radiator Mounting:  The location of the radiator may be different depending on whether your vehicle is equipped with an air conditioning condenser coil.  Vehicles without the A/C coil will be able to cheat the radiator into the grille or radiator support area.  This will require modifications to the lower radiator support and will also require a modification to access the filler neck.  By cheating the radiator into the grille area, a mechanical fan can be used.  NOTE:  All of our radiators can be mounted directly inside the radiator support core.  The radiator cap will remain in its original position.  If your vehicle is equipped with air conditioning, the radiator will be limited to being flush with the radiator support bracket.  The A/C coil must be mounted on the front side, directly inside the radiator support area.  If you keep the spacing between the A/C coil and the radiator to a minimum of 1/4", then you will have space available for mounting the electric pusher fans on the front side of the A/C coils. 

 

In order to maximize radiator-to-fan clearance, you must mount the radiator as far forward as possible.  To achieve this, the lower section of the S-truck fan shroud will need to be cut so that it is a flat piece that only holds the rubber cushions.  The lower portion will need to be sheet metal screwed to the chassis once the proper location has been determined. The upper mounting will require two small pieces of steel strapping that will retain the upper portion towards the front grille.  The radiator cap should be changed from the standard GM cap to the aftermarket octagonal cap to allow extra clearance for cap removal.  Make sure that proper cushioning is provided between the radiator and brackets.  The AA radiators offer both key stock and dowel pin supports for early and late model lower mounting applications.

 

Lower Radiator Hose:  On late model engines, the heater hose connection is an integral part of the lower radiator hose.  This connection can either be extended to the passenger side of the new radiator or it can be spliced into the lower hose.   GM has available a special "T" connector for the splicing.  The GM part number is #15617959, and was originally used on the Chevy Astro Van 4.3 engines.  The lower radiator hose can be made up by modifying a standard Goodyear radiator hose #61460 or Napa #FF254.  There are numerous combinations to make up the necessary connections and we suggest that you work closely with your local auto parts store.  Quite often you will need to use special reducer bushings that will neck down a 1-1/2" I.D. hose to 1-1/4".  These bushings are readily available at most auto part stores.

 

Upper Radiator Hose Connection:  In order to install a large engine-driven cooling fan, you will be required to route the front radiator hose directly behind the driver's side alternator position.  If you are not going to use the engine-driven fan, then the conventional thermostat housing can be retained.  When using the large fan that requires additional clearance, we recommend using a thermostat housing from a 1976-78 Chevy Monza V8.  This housing has a 1-1/2" diameter hose connection that will require a bushing when used with the new radiators.  The best hose for this application is one that was originally used on the Pontiac Firebird, Goodyear No. 60625, or a portion of a lower 1986 Camaro hose can also be used.  rad hose connect

 

Water Pump:  We have found that by using the long-style water pump (from Chevy vehicles 1978 & newer) in conjunction with our motor mounts, PN713107 (4WD) or PN713111 (2WD), you will have an easier time finding the necessary brackets required for mounting the engine accessories.  If your S10/S15 was originally equipped with air conditioning, then it will require the use of the long-style water pump.  The short version could be substituted to obtain additional clearance for a conventional fan, but bracket modifications will be required for installing the power steering and alternator.

 

Thermostat Housing:  The thermostat housing should be from a 1991 Caprice or a 1977 Monza V8.  The design of this housing will allow the radiator inlet hose to be angled towards the firewall, allowing for a better hose connection to the radiator.  The late model 1986 & newer Chevy TPI thermostat housing has the outlet installed directly towards the radiator.  This housing must be removed and replaced with an Everco #W2488.

 

We offer FLOWKOOLER high flow water pumps and thermostats.  These water pumps produce 22% more water pressure inside the block and are 32% more efficient than other water pumps on the market. 

 

Temperature Gauge:  When converting to a V8, you must use the stock V8 sending units.  These units will be compatible with your stock S10/S15 gauges.  For the early S10/S15 vehicles that are using the electric temperature senders, we have discovered that they will vary up to ten percent (10%) on accuracy.  We suggest that if you are having a heating problem, you might consider installing a temperature gauge that is mechanical and not dependent on the electrical sending unit.  This will require a new gauge that is available at most auto part stores.

 

ALTERNATOR:

Your stock V6 alternator can be retained by simply switching the pulley to one used on a V8 alternator.  The mounting brackets must be changed to the correct GM V8 alternator bracket and adjuster.  If you are replacing a 4 cylinder engine, we recommend that you purchase a new GM V8 alternator to provide the correct amperage. 

            GM ALTERNATOR BRACKET    GM# 14081227 (Adjuster) 

            GM ALTERNATOR BRACKET    GM# 14015533 (Front Bracket) 

            GM ALTERNATOR BRACKET    GM# 6262934 (Spacer)

 

STARTER MOTOR:

When removing the 2.8 V6 engine, your original starter motor can be retained for use with the V8 engine.  If you are replacing a 4 cylinder, you must purchase a new GM starter, 1982 or newer.  This starter is much more durable and will provide longer service for your conversion.  It is also recommended that you replace your V6 starter with this new starter.  Some starters have a larger body diameter.  These starters are generally the ones used with the larger flywheel (168 tooth).  If you stay with the number listed at the end of this sentence, you will find that there is no problem with starter motor installation or with the engine position.  (GM #1108400 for 168 tooth flywheels or GM#1108789 for 153 tooth flywheels, or Part No. 3510M, Starter--Remanufactured).

 

FUEL PUMP:

When installing a V8 into your S10/S15, you can use either a mechanical or electric fuel pump.  It's much easier to use an electric fuel pump, rather than trying to fit your mechanical fuel pump in an area that would require possible frame modifications.  Electric fuel pumps are readily available from most auto part stores and offer a wide range of pressure ratings for your block. 

 

If your S10 was originally equipped with an electronic fuel injection, your vehicle will be equipped with a high pressure fuel pump that is mounted in the gas tank.  These pumps are not compatible with carbureted engines.  The pump must be removed or regulated to a pressure of 5 to 7 pounds (carbureted blocks).  We recommend a Holley fuel regulator, Part No. 12-803, for use with these applications.  On engine installations that are going to use the Chevy V8 TPI engine, you will need to use the high-pressure fuel pump, along with the appropriate return line.  The fuel supply line should be 3/8", and the return line should be 5/16".   If a charcoal cannister is being used, then a 1/4" line is also required.  Make sure these items are secured to the frame rail with the proper rubber cushioning.

 

AIR CONDITIONING:

Your S10/S15 is equipped with an R4 radial compressor.  This compressor has been used since 1973 on a variety of V8 engines.  Brackets for your new V8 engine should be fairly simple.  Due to the new location, you will be required to modify the wiring harness and lengthen your hoses necessary for the V8 engine.  On both 2WD & 4WD conversions, an A/C evaporator housing cover is available to assist you in making the necessary clearances.  This housing is normally necessary for exhaust and block clearance when retaining the air conditioning.  The cover is AA PN716421.  To install the new cover, you should remove the housing from the firewall for proper cutting and assembly procedures.  AC evap hsg

 

OIL FILTER:

On 4WD conversions, you will need to remove the stock V8 oil filter and replace it with a bypass oil filter adapter.  The clearance is necessary for the front driveshaft.  The new oil filter mounting plate can be installed in the engine compartment.  We offer a complete kit that includes hoses, bypass adapter, and new filter mounting bracket.  On 2WD conversions, there is plenty of clearance so that the stock oil filter can remain in the original position.

 

POWER STEERING:

We have found it best to substitute a V8 power steering pump in place of the original V6 pump.  Even though they both have the same capacity, we believe that the V8 pump will permit the use of stock GM mounting brackets.  These brackets can be found on 1981-1984 GM full-size "C" series pickups.  In addition to these brackets, you will also need to obtain the correct V8 pulley for proper belt alignment.  This pulley can be single or double groove - depending on whether you choose to use air conditioning.  The double groove GM pulley is #14023173.  There are several variations of brackets for mounting the power steering pump.  You must pick a power steering pump installation that is compatible with your engine equipment.  Some brackets require tapped holes in the heads and exclusive use with the long style water pump, while others have alternate mounting positions.

 

It may be possible that you will be able to retain the original V6 power steering high pressure hose, depending on the model of your new V8 pump.  You may need to use a V8 high pressure line since they use a larger fitting for connecting to the pump.  The low pressure return line normally requires lengthening and possibly rerouting to allow for ample clearance around belts and pulleys.

 

Steering Column Shaft:  The plastic shield that is installed over the flex coupler of the steering drive shaft will need to be shortened or removed for clearance around the new V8 exhaust system.  On vehicles 1982-85 that are having steering drive shaft clearance problems, you may need to make a steering column mounting location change prior to engine installation.  The modification is to move the mounting holes on the firewall so that the column will enter into the engine compartment 3/4" further outward than the original location.  This will require re-drilling the firewall mounting holes which changes the angularity of the steering shaft and provides additional clearance for the steering column housing.  This modification should be done prior to the installation of the new engine. 

 

By performing this modification, you will be able to avoid any special modifications to the driver's side exhaust manifold.  The plastic shroud over the steering drive shaft can also remain unchanged.

 

FIREWALL MODIFICATIONS:

Your S10/S15 firewall and floor pan areas are very narrow and, in most instances, will need some slight modifications.  We have found that by using a 3 pound sledge hammer, it will provide adequate leverage in creating the required clearance.  The body seam between the floor pan and the firewall seems to be the biggest problem in clearance.  This can easily be taken care of by bending the seam over.  In some instances, additional clearance may be needed near the bottom corners where the firewall and floor pan meet; however, if you modify your transmission (removing the transmission ears), these modifications can be avoided in most cases. 

 

A body lift will provide additional clearance between the transmission and the floorboard area.  Depending on which motor mounts and which Chevy distributor you are using, you will need to determine the firewall clearance requirements.  If a large HEI distributor is being used along with AA motor mount P/N 713107, you will be required to recess your firewall a 1/2" for necessary clearance.  We suggest that you do the necessary modifications at assembly time in order to keep firewall modifications at a minimum.  Certain stock cast iron manifolds will require additional firewall clearances on the passenger side when using air conditioning and additional clearance may be necessary on the driver's side near the throttle entry area.

 

EXHAUST: 

We offer headers for Chevy V8 2WD and 4WD applications.  Our "SlickFit” exhaust systems ARE NOT approved for use on smog-legal vehicles.  These headers can be used on all early and late model cylinder heads.

 

In order to retain the smog legal status on your vehicle, you must consider the use of stock cast iron manifolds.  The only manifolds that will be legally accepted will be the 1982 & newer low performance Camaro and Firebird exhaust manifolds.  These manifolds are very compact and the main exhaust remains level with the exhaust ports. In order to use the Camaro/Firebird manifolds, your engine must be equipped with cylinder heads that were manufactured from 1978 & newer.  These particular cylinder heads have provisions for mounting the newer manifolds.  The difference is that these manifolds have an extra tapped hole at the rear on the passenger side.  Without the correct heads, you will not be able to use the proper stock cast iron exhaust manifolds.  When using the cast iron manifolds, the oil dipstick tube must be installed on the passenger side of the engine compartment.  If your engine is equipped with the dipstick on the driver's side, you will find major interference problems with the stock exhaust manifolds.

 

Passenger Side Stock Exhaust Manifold:  The flange connection must be very close to the back of the engine, and the correct manifold will have a 2" diameter outlet with the stud bolt installations already in position.  If you select the high-performance manifolds that have the 2-1/4" diameter outlet, you will find interference problems with both the frame rail and the firewall.  The correct manifold from the Camaro/Firebird can only be used with cylinder heads 1978 and newer having the double-tapped hole at the back port location.  manifold PS

 

Driver's Side Stock Exhaust Manifold:  The manifold must drop between the third and fourth port on the driver's side.  The clearance between the stock manifold and the steering drive shaft is so critical that you may require special modification to the stock manifolds.  This modification involves surfacing the flange area of the manifold approximately 1/8".  This modification will allow additional clearance between the manifold and steering drive shaft.  If your engine is not equipped with the dipstick on the passenger side, you will find severe interference problems between the driver's side manifold and oil dipstick tube.  manifold DS

 

ELECTRICAL / WIRING CONSIDERATIONS: 

Ignition System:  Your S10/S15 was originally equipped with an HEI distributor.  If you are installing a V8 with an HEI distributor, the stock S10/S15 wiring will plug right into the distributor.  If, however, you are using a point-type distributor, you must obtain a new coil and resistor and will be required to rewire the ignition system.

 

Wiring Modifications:  Most engine conversions will require elimination of the ECM (Electronic Control Module).  If you wish to keep the ECM, you will need to change the components to a unit compatible with your new engine.  We suggest that you obtain the necessary GM manuals when rewiring the system.  None of the existing V6 sensors will be compatible with your new engine.  If you were using an HEI distributor, you will find that the existing V6 plug will fit your new distributor.  If you change to a point-type distributor, you will need to change the wiring so that it includes a resistor and coil.

 

Engine Knock Sensor:  On Chevy engines that are equipped with the computer controls, you will find it necessary to install an engine knock sensor.  This knock sensor controls the timing of the engine computer and must be installed in an area compatible with the engine block.  The engine knock sensor can be retained by using a 45 degree brass elbow, Dorman #490-117.  (A small amount of grinding may be required on the motor mount for proper clearance). knock sensor elbow

 

Tachometer:  If your vehicle is equipped with a factory tachometer, you will need to have it re-calibrated for use with the V8 engine.   

 

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