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Vortec Engine Conversion

The Vortec V8 engines have become a very popular conversion into the later Jeeps. After David Herrera heard of the ones we had previously done, he decided that he wanted one installed into his 1982 CJ 7. He was also able to see the final results in one we did for Sam, owner of Pomona Gear. So Pomona Gear and Hicks 4x4 joined forces to do this project.

vortec engine conversion

David's Jeep came originally with the 4.2 six cylinder and T 5 transmission. He has the Dana 44 in the rear and the Dana 30 up front with 4.56 gears. He has 33" tall tires and Detroit Lockers front and rear. He had the combination for some good 4 wheeling except for the horse power.

The first thing was to get the engine and transmission. Since he had the overdrive in the T 5 he also wanted one in the new package. We picked up the package from West Coast Auto Parts in Montclair, Ca. We got the Vortec 5.3 engine, 4L60E automatic transmission, stock wiring loom for the engine and computer. Tony was very helpful to make sure that we had everything we needed to do the job. Since West Coast Auto Parts only deals in late model vehicles we were assured that we got a very low mileage engine and transmission.

vortec engine conversion

Now that we have the engine in hand we can start ordering the rest of the parts needed to install the engine and transmission. The first thing we did was to ship the computer and wire loom to Fuel Injection Specialist in San Antonio, TX. They modified the wire loom and reprogrammed the computer. When we got the loom back we only had to hook up 4 wires. The rest of the connections plugged into the original sensors on the engine and transmission.

While we waited for the return of the loom and computer, we ordered the rest of the parts we need to do the installation. This way we had everything we need before we even pulled the stock engine and transmission. We ordered the motor mounts and adapter from Advance Adapters in Paso Robles, CA. We also decided to order a larger radiator with the GM off set inlet and outlet. 1-800-RADIATOR had one available that bolts right in with more cores than the stock one. Since we were changing from a standard transmission to an automatic we ordered a heavy duty Hayden transmission cooler and B&M shifter and to make sure the Jeep ran cool we also got a TorqFlow electric fan. These were all available from your local big chain parts stores (Auto Zone Kragen or Pep Boys). They also had available the K&N filter we were able to use on the stock M.A.F.sensor. The high pressure fuel pump had to be ordered from one of the larger independent parts houses that carried A/C Delco or Delphi. The last thing we had to order was the EVAP Canister Vent Valve Solenoid and a throttle cable from a later model C1500. Those had to be ordered from the local GM dealer.

vortec engine conversion

Once we had everything in hand we were ready to start removing the stock engine, transmission and transfer case as a package. To make it easier we pulled the grill and fenders. We disconnected the wire harness from the firewall and removed it with the engine package. With the engine out of the way we could now remove the stock motor mounts off of the frame. Since they were bolted in we were able to use the top front holes to bolt the new ones temporarily in place. This gave use the position we wanted for clearance at the back of the engine. Once the engine was out we could isolate the wires we wanted to reuse. The wires included water temperature, oil pressure, starter solenoid, switch wires from transmission and transfer case, main power source and keyed power source. All the other wires we needed were in the modified Vortec wire loom. The next thing was to adapt the two stock sending units to the Vortec engine. For the water temperature sending unit we drilled and taped an existing hole in the passenger side head and for the oil pressure sending unit we ran a tee off of the stock Vortec sending unit. We also took the time to reroute the fuel line up and toward the center of the firewall. This made it easier to connect the fuel line to the engine because the fuel rail connects toward the rear of the engine.

vortec engine conversion

It was now time to install the adapter onto the 4L60E transmission and bolt on the transfer case. If you have to change the output shaft be sure to do that ahead of time. In our case we were able to use the stock 4WD shaft in the transmission. We did how ever have to change the input shaft in the Dana 300 to match the output shaft in the transmission. We decided to reseal it at the same time to prevent leaks later on. We also had Mike at the Toy Shop in Pomona, CA reseal the transmission and install two standard size fittings for the transmission cooler lines. He also modified the transmission oil pan on the passenger for extra drive shaft clearance. After we bolted the motor mounts to the engine we were ready to install the package.

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Now with all the prep work done the engine package is ready to install. With the frame motor mounts already installed the forward position is already established. With the engine setting in the frame we used a floor jack to raise the rear of the assembly up to a fairly level position. We slid the engine toward the drivers side an extra inch for extra drive shaft clearance. With this distance established we were ready to bolt the motor mounts to the frame mounts. Now lifting the rear of the assembly to the desired height we bolted in the cross member. With about an inch clearance between the cross member and the transmission oil pan we determined the distance between the adapter mount and the cross member. We used a late GM 4WD transmission mount and some square tubing as spacers to mount the rear of the assembly. (You can also order a mount kit from Advance Adapters).

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Now with the engine in place and frame mounts welded, we started with the drive shafts. Once we got the new measurements we took them to Randy at Driveshaft Specialties in Azusa, CA. While we waited for the drive shafts we assembled the new radiator, electric fan, transmission cooler and grill. We put the electric fan in front of the radiator and because the radiator was thicker we had to trim the inside of the grill slightly. With the radiator/grill assembly held in place by the two top braces and bottom bolt we worked on the radiator hoses. By using the stock hoses for a late model GM truck we were able to modify them to fit. In the modification we had to join two halves together with 1 1/2 inch tubing. This worked good because on the bottom hose we needed a 1/4 inch nipple for the preheat hose to the intake. Next was to hook up the two heater hoses. With the transmission and transmission cooler all in place we ran the lines to connect the two. You can run transmission hose or 5/16 inch metal line with hose connectors. Since we were working with the transmission we decided to install the shifters. The B&M shifter was a matter of running the cable, hooking up the neutral safety switch, back up light switch and bolting down the shifter. We had to heat and bend the transfer case shifter so it would come up in the same position as stock. While we were on the inside we installed the new throttle cable. To do so we had to slightly enlarge the hole in the firewall and shorten the inside portion of the cable. We did this with a cable crimp.

The Delphi high pressure fuel pump we used was mounted inline just ahead of the fuel tank. The pump will got wired when we wired the rest of the loom. The next thing we had to install was the EVAP Canister Vent Valve Solenoid. The solenoid was attached to the EVAP Canister with a short piece of hose and mounted into position.

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Now with the drive shafts back in hand and installed we knew how to route the exhaust system. If possible try to get the head pipe with the engine. This will give you the converters and the position of the O2 sensors. When building the exhaust it is important to keep the converters close to the engine. They need to run hot to function properly. It is also important to keep the sensors in the same position as stock.

vortec engine conversion

The wiring was the last thing we had to do. Most people think that the wiring is the hardest part of the conversion. So did I until I did one with the Fuel Injection Specialties modified loom. The loom is labeled and positioned to lay on the engine and connect to all the stock sensors. Once we had everything plugged in, we routed the main loom over to the driver side where we would mount the computer. We now hooked up the stock wires we removed with the engine and cut off the ones we didn't use. We still had to hook up the fan and fuel pump. The wire for the fuel pump is in the loom, it just needed to be extended to reach the fuel pump in the rear. When we wired in the fan we used a relay. This way we wouldn't overload the system. The rest of the wires we hooked up from the loom were the keyed power, check engine light, tach (if you have one), oil pressure (optional, we already had the stock one hooked up), water temperature (optional, we already had the stock one hooked up), and AC clutch (optional).

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With everything hooked up and fluids in everything we were ready to make it run. We first bled the injector rail by turning on the pump and releasing the air from the pressure test fitting. This took about 4 or 5 times to bleed all of the air out. Once it was bled after a few cranks it started right up. After running it for awhile we were able run a scan on the system to be sure that all of the sensors were working properly. Everything checked out OK but we still needed to drive it for at least 60 miles to make sure everything was properly. Once the second running proved out OK it was ready to take to the smog referee and get a new smog sticker. This Jeep had to pass California smog regulations.

This technical article was written with the intent of helping you do this conversion yourself. If you find it a little difficult for you then we can do it for you. This conversion can be done at either shop. We have the facilities to do it at Pomona Gear and Axle Repair in Pomona, CA. or Hicks 4x4 in Williams, AZ. If you have any comments or suggestions about this article please feel free to contact us at either or Happy Conversions!