The 400 will have an intermediate clutch pack and center support that adds extra length. I'm guessing that the bell housing would be deeper since there is a lot of talk about GM converter cores being thicker and/or better giving them better options.
AG.

Last edited by turbobitt; 08/25/16 05:22 PM.
1970 Challenger w/572 Hemi street car and my pride and joy. 1986 T-Type with 272 Stage 2 Buick V6 engine - True 8 second street car. Just updated the engine and put down 928 HP @ 35# boost to the ground on chasis dyno. 1976 Cee Bee Avenger Jet Boat - 460 Ford powered.