Installation of a Tremec TKO 5-Speed

My car came with a Muncie M20 4-speed. Although the Muncies were pretty good for their time, newer transmissions are quite a bit nicer. The internal rail shifting mechanism found on recent trannies allow much smoother shifts than the external rail muncies could do. A steeper 1st gear (3.27:1 compared to 2.52 for the M20) makes it easier to drive in slow traffic. A 0.68:1 overdrive 5th gear coupled with my 3.08 rear gears means 1700 rpm @ 60 mph. When the Corvetteforum arranged a group purchase it was time to whip out the credit card and get busy.

The torque mount visible at the rear of the tranny has to be removed to clear the Corvette crossmember. The big job with installing a Tremec TKO in a car that came with a manual transmission is that the crossmember is welded in instead of bolted as on the automatics. The Muncie is small enough to be removed with the crossmember in place. The Tremec is slightly larger and won't go in without removing the crossmember.

I cut the crossmember out with a saw-z-all. It was actually surprisingly easy to cut it out, as the steel is not very thick. I then welded on brackets on the piece that had been removed. Here's a look after welding on the brackets and a general cleanup and primer:

The modified crossmember was then test fitted on the car:

After some satin black paint holes were drilled and it was bolted down:

Next issue was the shifter location. The Muncie uses a side mounted shifter with external shift rods. The Tremec, using an internal rail mechanism, has a centrally mounted shifter. Here's a shot of the console with the shifter.

The left part of the hole is the factory hole used for the Muncie. I chose to cut the hole large enough to where I can remove the shifter without dropping the tranny.

An aluminum plate was fabricated to cover the excess hole and the factory boot was used for the actual shifter stub:

Finally a bracket had to be made to move the shifter handle over to the left so that the stock console will fit. The first iteration of the bracket didn't turn out well.

This bracket was way to flimsy and I could feel the thing flex and bend when shifting. It also placed the shifter too far forward, as shown in the following picture.

This is while in 3rd gear and you can see how close it is to hitting the edge of the gate.

The next version of the bracket turned out better.

It was built by welding two pieces 1/8" thick angle iron together. The weld was brought out to the bends so the part that sees the most stress is a solid 1/4" thick. I think something inside the tranny will break before the bracket gives.

And to wrap things up, here's a shot with the new bracket with the tranny in neutral.