I am trying to figure out what all needs to be changed for this swap: I have a built 455 and a “needs to be rebuilt” TH400 for a 1965 Cutlass that currently has a 330 & a Jetaway. I know the trans cross member will have to be moved back. From what I’ve read the frame probably doesn’t have the proper holes for the trans cross member but they can be added. I don’t know what tail shaft length I have but I believe it came out of an Olds big car from mid 70s. Do I want the shortest tail shaft I can get or does it matter? I know I will have to swap out the drive shaft yoke and shorten the drive shaft. I have a yet to be installed 9” from John’s Industries that will further complicate the drive shaft length. And the parking brake cables will need to be changed. What else am I missing?

 

You've pretty much got it. The frame definitely did not come with the crossmember holes drilled for the TH400, as it was not offered in the A-body line until the 1967 model year. A big car TH400 will be a long tail. With the rear end swap you're looking at a custom driveshaft anyway. I'm sure you know to just use the 1965 motor mounts (Anchor P/N 2261). If you are running manifolds, W/Z are your best choice.

 

When I worked on a friends car, (72 Cutlass) it did have a long shaft turbo 375? trans). The driveshaft was marked Camaro in yellow junkyard paint and seemed to be unaltered. So you may find a ready made shaft for your application but a custom one may be easier to find and are not that expensive.

 

The tag on my tranny reads 75-OR-65582 which I assume means was from a 1975 Olds. I didn't measure the tail shaft but I would guess it is 9" long? Since the TH400 will need to be rebuilt, I have to have a driveshaft made, and drill holes for the cross member, is there an advantage to having a short or keeping the long tail shaft?

 

When you have the trans rebuilt they can very easily make it a short shaft.
On you application long or short would be no big deal, you have to have a drive shaft made or find one of the length you need.

Gene