Topic: Pre-'75 Transmission Crossmember In '75-81 Car?

[Orange 81 T/TA]

Hello all,

It's been awhile since I've been around. I'm sure this topic is covered somewhere, but I've been unable to find it...

I'm looking to swap a 200-4R into my '81 TTA (TH350C). I know I can just move the crossmember back and drill new holes, but I'd rather not. I'd like to just throw in a TH400 crossmember from a pre-'75 car, but so far I haven't been able to determine if that will even work.

Will it? What is the reason for the mid-generation split on crossmembers?

Worst-case scenario, I'll spend the $200ish for an aftermarket conversion crossmember.

[Wallington]

Some also cut of the transmission mounting tab and weld it on the other side, but I can't recall offhand which they used. I'd just source a new xmember for the 200r4 knowing it works, I have the G-Force unit here.

[Orange 81 T/TA]

Some also cut of the transmission mounting tab and weld it on the other side, but I can't recall offhand which they used. I'd just source a new xmember for the 200r4 knowing it works, I have the G-Force unit here.

I've been looking at the G-Force crossmember and have more or less decided that's the one I'll go with.

After doing some more research, it seems the '70-74 crossmember is about 1.25" narrower than the '75-81 crossmember. So I'm doubtful it will work without some serious modification.