2nd gen Camero rear end's swap right in i'v heard. find 1 in a yard, measure to be shure it will fit.
you couldn't use the original rear with a T400 anyway, it's a torque tube rear, and likely 4.11 gears at that. Luckily being my car is a PG car, I have 3.55 gears
Why run a T400? BB's don't fit in a early 50's Chevy without a lot of work, and the T400 will take a lot of power from a SB, T350 is a better choice. also, you will need to relocate the e brake stuff, it's in the way for a V8.