I recently installed a tremec 5-speed in my 71 using the factory crossmember, only now it is removeable. The only thing left is the mount. I would like to fabricate my own but I need to know where the tailshaft was positioned originally with the muncie installed. Specifically the distance left to right from frame-rail to frame-rail and up and down from the crossmember. If I knew these dimensions I would be set unless you have any better ideas?

 

This is how I had to modify my mount to make it work.

Start viewing from this photo from this link.

http://www.acc-controls.com/vette/im.../image386.html


Hope it helps

 

Just to start. Can you place the original bracket, that mounted the factory shifter, to the crossmember? This will help you solve your problems. If you look your Muncie you will see a ring cast into the tail housing. Now look at the bracket. You will see a rectangular slot cut into the bracket. The rectangular slot is vertical. The ring cast into the Muncie tailpiece fits into this slot. Also, if you push (with your hand) the output yoke of the Muncie back into the Muncie (the output yoke slides back and forth on the Muncie tail shaft) the yoke will contact this bracket, but just barely. If you push the yoke into the transmission it almost will not interfere with the bracket.

I now have a ZZ4/stock bellhousing/Muncie stack sitting in a spare frame. I also have the stock shifter mounted to the factory shifter/crossmember bracket. And the Muncie has the stock output yoke attached. The frame has a welded in crossmember. It is supposed to be a 1969 frame. The ZZ4 is a small block GM engine.

I haven't learned how to send pictures yet. Is there something I can do to make a measurement? The elevation of the output shaft and yoke, that is elevation relative to the crossmember, depends on the thickness of the transmission mount rubber/poly bushing. I have installed a rubber bushing that is the same height as the original stock bushing. The dimension of my output yoke, relative to the crossmember, should be same as stock.

I appreciate your problem. I also have a 1970 BB. I have a Richmond 5 speed that I'll someday have to squeeze into this car. I'll have to modify the transmission mounting bracket. (I've installed a Richmond 5 speed many years ago. It is a really tight installation.)

Anyhow, is there something in the order of a measurement I can do to help??

 

I think the information you are looking for are the output shaft dimensions that establish the driveshaft angle. If you measure across the frame rails, the inside dimension should be 47". The output of the trans should be 24.5" from the left rail and 22.5" from the right. The center of the output shaft should be 4-4.5" down from the underside of the tunnel (on a solid body mount car). I put my Tremec up as far as it would go without touching the tunnel. Ended up about 4" down.

 

BBShark, thanks for those dimensions. Are those out of a book or did you measure those off of your car? I currently have the body off of the frame so the dimension you gave for up and down doesnt help much. Do you know how far the center of the output shaft is from the top of the crossmember?

 

40927, I got the measurements from my car. The distance from the output shaft center to the top of the crossmember is 2.75". I have my Tremec up as high as I can get it but it is essentially on the same centerline as my old Muncie. You might want to mount yours at 2.5" and shim up from there when you get the body on.

 

BBShark, thats good advice. I will do exactly that, thanks again.