what chevy engines will bolt up to pontiac th400
 

Looking at new crate engines either a 350 or 383 stroker, will they bolt up to my pontiac th400 tranny? Need an adapter plate?

With a common $60 adapter plate it will, available from Jeg's or Summit Racing.

Or an Ultrabell shield.

Why not go to a 454? Lots more torque to get big car moving? Not that much more money and lots more power.