I'm finally getting my 68's critical underparts back together and I'm about ready to drop the motor and transmission in. I've read numerouse times that a THM400 crossmember for a 69 is what was needed, but the mounting hole needs to be elongated.

Before I drop any money on a 400 crossmember I'd like to get some confirmation from those who have done this retrofit. Will the pinion angle be about right? If not, I plan to build a custom crossmember.

The previous owner hacked the old powerglide crossmember and made it work, now I want to do it right. For starters I'd like to see all then bolt holes filled. :D

-dnult

A friend of mine modified a ($50) TH-400 repro crossmember for my 700r4. Bowtie Overdrives makes a crossmember for the 700r-4. It was $150 the last time I checked.

I used the TH200, so I can't speak to much specific on the 700. However, all the T400 crossmembers have the mount pad offset toward the shotgun side by about an inch. You'll need to cut the mount pad off and re-weld it centered if you're running a small block with small block frame stands.

I probably should test fit and see what the tail shaft alignment should be and compare that to a THM400 crossmember. My main worry is that I can get it bolted up right, but the shaft alignment will be off.

-dnult

Dnult,
Bolt the trans to the engine and center your crossmember to trans mounting bolts. Your u-joints will take care of any missalignment. Remember a big block is offset fom a small block, so it isn't straight back to the pumpkin anyway. Also I don't believe the pumpkin is centered either.

Thanks TSJ, but the side to side alignment should not be a problem if my rear end and transmission are in line with one another (paralell) even though there is an offset. However if the tail shaft of the transmission isn't paralell with the rear end yoke in the vertical plane, then I'll have vibration problems even though the U-joints will allow it to technically work.

-dnult