IF I remember correctly the cross members are the same, BUT the TH400 mounts a few inches futher towards the rear.
TH400/TH350 Crossmember Beneath the running boards of your car you'll find the crossmember mounts into two rubber and steel mounts. We used to call them "pillow blocks" but I am not sure that the name is technically correct. Pillow Blocks attach to the car with two bolts. If you look closely you will see that there are three bolt holes. These allow the pillow blocks to be moved further toward the rear. No problems, same crossmember.
One thing I forgot to mention is that if you have a boxed (convertible) frame that they had a mount welded to the frame. When I changed mine I had to weld two brackets to the frame to get the cross member to mount with thw TH400.
Guys, The TH350 and TH400 crossmembers have different part numbers so there is a difference between the two. I think it has to do with how the emergency brake cables attach, but regardless, the difference is minimal. Duane
Thanks guys and thanks Duane. I picked up 2 the other day, one is for a buick so I figured I'd keep it as a spare and the other is from a 70 Lemans, so I guess I will sell that one. thanks again
