Trailblazer SS LS2/4L70E AWD Swap into 1984 C4 Corvette 4+3
05-17-2013, 09:24 AM
#21
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The engine and transmission have been successfully mounted in the vehicle. The C5 corvette batwing oil pan could not be used, as we were unable to load the engine/trans combo from the top and try to install the pan with the engine mount weld extensions in the way. So, I am resorting back over to an F-body oil pan, on its way to my home.
For the engine mount weld extension, we chose to use a 4'' long about .375 in thick square tube obtained from a local metal salvage. We allowed for about 1 inch of overhang onto the K member and cut the piece to fit the dimensions of the car before welding. The total extension is near 3'', as described by Corvette Central. The holes for the engine mounts required a Cobalt 5/8'' drill bit, which even still required us to sharpen the bit about 3 times to get the holes punched.
On the transmission mounting, we chose to use the Dana 44 rear diff coupled to the Dana 36 C-beam coupled to the 4L70. The reason for using the Dana 36 C beam is that it is an inch longer than a Dana 44 C beam. This is because the actual Dana 44 rear diff yoke is an inch forward in car over a Dana 36, so they shortened the Dana 44 C beam to make the overall lengths identical. Using the Dana 36 C beam bought us an extra inch forward in car, which allowed us to not have to mount the engine right on top of the firewall. This allowed good clearance for wiring, servicing the engine, etc. We did have to remove a chunk of fiberglass from the driver side area near the gas pedal location to accomodate the engine. However, we did not have to remove any fiberglass on the passenger side, and the original wiring grommets were left in tact to the blower assembly/old L83 wiring. We still had plenty of room to the steering rack/K member on the pulley side with the additional inch forward on the powertrain. We also chose to mount the engine slightly biased towards the passenger side to allow better power steering pulley clearance. This made space tighter to the heat core ports on the engine, but we think we can cut down those tubes and make it work. No A/C in the car so we did not have to worry about compressor clearance.
Last, I have decided to go with a 05 TB EXT shifter. Fitting it will be challenging with the C-Beam trans in the way, but we think we have an idea how to do it. I attempted to use a C4 automatic shifter, but the total throw length of the shifter is shorter than the trailblazer's 4L70 needs, so I have to scrap that idea.
For the engine mount weld extension, we chose to use a 4'' long about .375 in thick square tube obtained from a local metal salvage. We allowed for about 1 inch of overhang onto the K member and cut the piece to fit the dimensions of the car before welding. The total extension is near 3'', as described by Corvette Central. The holes for the engine mounts required a Cobalt 5/8'' drill bit, which even still required us to sharpen the bit about 3 times to get the holes punched.
On the transmission mounting, we chose to use the Dana 44 rear diff coupled to the Dana 36 C-beam coupled to the 4L70. The reason for using the Dana 36 C beam is that it is an inch longer than a Dana 44 C beam. This is because the actual Dana 44 rear diff yoke is an inch forward in car over a Dana 36, so they shortened the Dana 44 C beam to make the overall lengths identical. Using the Dana 36 C beam bought us an extra inch forward in car, which allowed us to not have to mount the engine right on top of the firewall. This allowed good clearance for wiring, servicing the engine, etc. We did have to remove a chunk of fiberglass from the driver side area near the gas pedal location to accomodate the engine. However, we did not have to remove any fiberglass on the passenger side, and the original wiring grommets were left in tact to the blower assembly/old L83 wiring. We still had plenty of room to the steering rack/K member on the pulley side with the additional inch forward on the powertrain. We also chose to mount the engine slightly biased towards the passenger side to allow better power steering pulley clearance. This made space tighter to the heat core ports on the engine, but we think we can cut down those tubes and make it work. No A/C in the car so we did not have to worry about compressor clearance.
Last, I have decided to go with a 05 TB EXT shifter. Fitting it will be challenging with the C-Beam trans in the way, but we think we have an idea how to do it. I attempted to use a C4 automatic shifter, but the total throw length of the shifter is shorter than the trailblazer's 4L70 needs, so I have to scrap that idea.
09-14-2023, 03:15 PM
#23
TECH Senior Member
