[thepontiacman]

a friend is putting a th400 and 400 in a 81 trans am, what crossmember does he need to use or can original th350 crossmember be modified?

[stuta]

I had a similar experience 40 + years ago with a 72 Formula. Yeeesh, that was a long time ago
I had pulled a 350 engine with auto trans, and replace it with a 400 engine and 400 trans. The shop that helped me was able to use the original crossmember. He told me he turned it around and just had to mount it a little further back to match up to the longer 400 trans mounts.
My 400 trans came with the matching yoke and driveshaft that fit the Formula too.
Sorry I can't give you any more details, as I didn't do the install myself. But that was a concern of mine too at the time.

Your buddies 81 will really come to life with that combo...I know I had a blast in my ride.

[thepontiacman]

Yes, I knew about using the original crossmember and modifying it as you describe.

Wanted to give him options to do it right.

thanks

[muscle_collector]

back in 1980 i bought a new indy 500 ta and almost immediately pulled the engine and trans and put in a 400 with turbo 400. as for the crossmember, i cut the mount off and mounted it on the other side and it worked perfectly.

[thepontiacman]

Thanks. I will let him know.

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[Skip Fix]

I tried the mount tab on the other side for my 500" IA/Camaro TH400. The deep pan hits but it cam be sectioned.. I ended up using a G Force/Summit crossmember,

[78w72]

i had a 455/th400 from a 74 firebird in a 78 t/a... i just used the original 74 th400 cross member & had to drill new mount holes in the frame an inch or 2 back. much easier than re-weldng the mount tab.

[Aus78Formula]

Flipping the mount around or moving the mounting tab over is a useful trick. You can easily make a larger slotted tab if needed for adjusting location easier. A spare mount may be useful for comparing mods and measurements to.