My brother and I have decided to run a th400 instead of a th350 in our race car. The car has the original 350 crossmember. Do we have to find a 400 crossmember or is there another way to do this? I know there can't be too many 400 crossmembers floating around out there.
Todd, The crossmembers for a TH350 and TH400 are identical except the TH400 has a slot cut into it for the parking brake cable. All you need to do is reposition the crossmember for the longer transmission and you are golden. Duane
Thanks Duane. I don't see us needing the parking brake at the track so I guess this will be pretty easy. :TU:
Todd, You can still use the parking brake. Just route it over top the crossmember instead of through it. Duane
I'm going from a TH350 to a TH400 as well, and have a related question. Should it be okay to just slide the crossmember back and drill new holes (assuming everything is lined up properly)? My frame has a slight upward indent where the original x-member location is (pictured), not sure if that provides any purpose? It looks like it may provide some extra reinforcement to hold up the tranny, and it also raises the tranny a bit. If I were to slide the x-member back in a new location, iit looks like it would bolt up a bit lower, as it doesn't have that indent in the new location. Does it seem like that slightly lower angle and less structural rigidity will cause an issue? Thanks! :bglasses:
Ethan, Just slide the crossmember back to use the rear holes.. that's where the factory intended the th400 to bolt up, they didn't change the frame for differenced between the th350 and th400 cars. If it does sit lower, then I can only assume that's how GM intended for it to be. FWIW... I also switched from a th350 to a 400 and had no problems at all, so I wouldn't worry about any "drop". HTH
Cool, thanks man. I guess I'll just have to set everything in there and see. I'm wondering if with the 455/TH400 combo it will bolt up even further back than the rear-most original holes. It sure seems like it will... guess I better get out the ol tape measure again...
