[sweeneybp]

I have a 79 T/A that came with a 301 and obviously a turbo 350 tranny. I recently installed a healthy pontiac 400 and also opted to convert over to a short tail turbo 400 tranny. When I installed the engine & tranny, I found out that the 350 crossmember didn't work. My question is what other GM crossmembers would be bolt in's. I tried to relocate the tab on the 350 crossmember to the other side of the member, but the cross member still hit's the tranny. I also realize I could drill new holes in the frame, but I would prefer to find a direct bolt in- If there is one. Thanks for the help

[TransAm525]

You can also just swap in an early F-body TH400 crossmember. Between E-bay, this forum, and your local wrecking yards (unless you live on the east coast), you should find one. If all else fails, Ames and Classic Industries sells the crossmember. You can also go the cheesy back yard engineering route (like the previous owner of my TA did when he installed the TH400) and just move the crossmember back by drilling new mounting holes in the subframe (I'm ripping mine out and installing a Art Morrison crossmember).

[firebirdcrazy1959]

I JUST BURNED TWO HOLES EACH SIDE OF FRAME BACK FROM THE OLD HOLES.USED THE 350 CROSS MEMBER.THE 70-74 SUBFRAME IS NARROWER.AS IS THE CROSS MEMBER.

[sweeneybp]

I have a 79 T/A that came with a 301 and obviously a turbo 350 tranny. I recently installed a healthy pontiac 400 and also opted to convert over to a short tail turbo 400 tranny. When I installed the engine & tranny, I found out that the 350 crossmember didn't work. My question is what other GM crossmembers would be bolt in's. I tried to relocate the tab on the 350 crossmember to the other side of the member, but the cross member still hit's the tranny. I also realize I could drill new holes in the frame, but I would prefer to find a direct bolt in- If there is one. Thanks for the help

[Skip Fix]

Bow Tie Overdrives has one for 200Rs that is the same length as a TH400.

What hit on your tab oncversion. Seems like it should be right on. Maybe have to cut it flat on the top somelike it is on the TH350 side.

[bbbad68]

i bought a new gm 400 cross member from a locale gm dealer. got the thing home and it was the identical to my 350 one. so i just drilled new holes and moved it back

[Skip Fix]

I've heard what Dennis said different frame widths.

[samssuperpro]

I've done it to all of my T/A'S welded the tab on the other side the thing is you need to have the correct mount. I use the 400 mount from a 72 bonniville 455-400 trans it's taller. Any problems let me know i"ll send pics

[rocky]

I install 400 turbo in my 79 years ago I got the correct 400 turbo crossmember from local gm dealer fit fine just had to drill new holes in the sub frame

[sweeneybp]

Guys- thanks for the advice. Mike Sams- please post the pic’s of your tab conversion, they would be helpful. With my tab conversion, the crossmember hits the pan on the opposite side of the linkage. It misses the holes by 3 inches. I had a deep pan installed, but it looks like it would still hit with a stock pan. TransAM525- which years of the F-body will fit?? I heard that the frame rails got widened in the mid 70’s?
Thanks again for the advice
PS- Your right- East Coast junk yards haven’t been very helpful in this restoration

[Dens71TA]

I don't think a '70-'74 TH400 cross member is going to fit a '75-'81 subframe. Its going to be too narrow. The TH400 was no longer used after '74 so there is no factory cross member for the later frames. The only way is going to be with fabrication.