So last night I just finished the swap of my Muncie M21 to a TKO500 5 speed and all I can say is wow! This is such a nice transmission. The swap it self was fairly straight forward but it required a new clutch disc because the Muncie was a 10 spline shaft and the Tremec is a 26 spline shaft. Additionally, I had to order a new transmission mount because the factory mount does not fit the trans.

I got lucky with buying the trans. I came across a guy who bought this Tremec for his Mustang and did not realize it was for a Chevy. He sent the details and measurements to SST and they confirmed that it was for a C3 Corvette but he knew nothing else about it. I bought it not knowing if it was good or not but it turns out it was freshly rebuilt and had never been used.

The transmission shifts very smooth and having that extra gear on the highway is amazing. I also prefer to shift pattern of a 5 speed where reverse is down and to the right as opposed to up to the left. My Muncie was recently rebuilt as well and it drove just fine but your talking an older design of a transmission as opposed to a newer design so the technology is just better.

The only other mod that I made was to add a removeable trans crossmember to make it easier to r&r the two transmissions.

My costs were:
TKO500 - $700
Removeable crossmember - $141
Trans mount - $240
New RAM clutch - $110
Bellhousing offset dial pins - $25
Clutch alignment tool - $4
Trans fluid - $33
Pilot bearing - $5
5 speed shift pattern plate - $28
TOTAL: $1286

Labor- probably about 25 hours

 

That is a really great price. I paid almost three times that amount for my kit. What rear do you have in the car? Good thinking on the removable cross member. Chevy should have done that starting in 1963. Jerry

 

I have a 3.70 with an LSD that I installed just before the swap. The car has an open diff with 3.36

 

Great work. I also installed a Tremec TKO600 5 speed in my 68. Please expand on the removable cross member. I have the plates where I need to cut the cross member and weld the plate in. Is this what you did or is the a full removable cross member you bought?
thanks

 

I had the plates. So I cut it about 2” outboard of the exhaust pass throughs. Then I started with the pieces in the car. I made sure they were vertical and welded them on. You cant really get an outside weld on top with the body on so I did an inside and outside weld on three sides and then just an inside weld on top. Then I did a test fit and welded on the crossmember part. Honestly, it was easier than I thought it would be.

 

were the plates solid steel plates pr the cutout style. Mine are solid plates. My concern as you mentioned is the top weld . With the solid plates I don't see how to weld inside only around the outside. I was always concerned with only 3 sides welded on the under car plates..

 

Mine were the cut outs. I got them from Modern Drive Line