1972 Chevrolet Corvette Scarlett Project Car - Six-Speed Manual

More Gears, More Fun - Installing an American Powertrain six-speed manual in our '72 project car

Jeremy D. Clough Jun 2, 2014 0 Comment(s)
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Bolt Transmission 2/34

11 Bolting the transmission mount into place. This is where it started to get fun: Not only was the downward-facing mounting bracket on the trans too wide for the mating surface on the crossmember, but with the height of the standard mount, the trans was pushing up against the underside of the transmission tunnel.

Trans 3/34

12 The trans crossmember, after being heavily modified to fit the T56 Magnum. Installing a new mounting surface, and then boxing it back in for strength, created a pocket for the trans mount to sit in. It also lowered the trans, obviating the need to remove fiberglass from the trans tunnel.

T56 Trans Installed Modified 4/34

13 The T56 as installed in the heavily modified factory crossmember. Note how deeply into the crossmember the trans actually sits.

Driveshaft And Flange Style 5/34

14 The driveshaft and flange-style yoke. Since the ’shaft came separately from the trans-installation kit, we needed to measure the length from the rear of the trans to the differential and send in that measurement. A driveshaft with the correct dimensions was then shipped out.

Dragvette Safety 6/34

15 Our Dragvette safety loop worked fine with the original trans but mounted too close to the new T56. As a result, we had to cut off the old mounting bracket and fabricate a new pair. Walden mocked these up in place and then welded them to the loop.

Install 7/34

16 The driveshaft was installed next, and the LS3 was now officially connected to the rear wheels. Since the loop mounted to the bolts that originally held the safety cable for the seat belts, we welded on an extra set of mounts for the cable and bolted it into place on them.

Remove Pedal 8/34

17 The pedal housing has to be removed in order to add the clutch pedal. After dropping the steering column and surrounding parts, we undid the four external bolts that hold the housing in place and removed it. Once out and disassembled, we bead-blasted it and painted it with some dull-metallic-gray Cast Blast paint.

Brake Pedal Return Weld 9/34

18 One advantage to having the housing out was the ability to weld back on this bracket for the brake-pedal return spring, which had broken off some time before. Without the spring, pressure from the brake system will keep the pedal up, though not enough to prevent the brake lights from burning all the time. Prior to this fix, I made do with a long coil spring zip-tied in place.

Stock Clutch 10/34

19 While the stock clutch pedal uses a stud on the side to operate the clutch, we needed a hole to mount the heim-jointed operating rod for our Wilwood master cylinder. I used a wheelie cutter to cut the welds holding the stud on the pedal, then dressed down the cut and painted it black to protect it from rust. Now, the new stud can be bolted into place once the pedal has been installed.

Reassemble Pedal 11/34

20 When reassembling the pedal housing, it’s important to reinstall the rubber bumpers that cushion the pedals’ impact with the housing when released. It’s the same part for the clutch or brake.

Master Cylinder 12/34

21 The master-cylinder kit for the hydraulic clutch assembly includes a reservoir, the Wilwood master cylinder and its pivoting bracket, and all the required mounting hardware. Even so, we wound up having to do a little fabrication to place the reservoir where we wanted it.

Mount Master Cylinder 13/34

22 After locating the holes on the firewall, we used a step drill to open them up so we could mount the master-cylinder bracket. We then used the four bolts to attach it to the firewall.

Install Threaded 14/34

23 The threaded rod that connects the master cylinder to the clutch pedal can now be installed by adjusting the rod to the correct length, then installing the Heim-jointed stud through its hole in the side of the pedal and bolting it into place there.


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