swapping bell housings from 250 to 400???

[grunex125]

Here's a question for you guys that have put the 400 motor in your trucks, are you finding it necessary to swap your bell housings to fit your transmissions or are they the same bell housings on the 250 as the 400's?

what about the clutch plates vs. input shafts on the transmissions? are they larger or smaller splines? I know I've touched on this topic before, but please bear with me on this. it is a topic that interests me greatly, but there seems to be a lot of dispute on the subject from my local mechanics, and curiosity is killing this cat.....lol

 

[73m819]

Input shaft should be the same, depends on the installed clutch disk which can be speced for what ever needed ( coarse/fine spline, thin/thick shaft) bell housing should bolt to a 400 855 block, I would use the 400 pressure plate though think the 250 will bolt up. now all this depends if the 400 had a auto or standard behind it, not sure if the auto and the standard have the same fly wheel, or if the torque converter is the fly wheel. If a standard was behind the 400 then everything "should" bolt up