a Body / swap to b body.

Is there a difference in the K from a to b body?
I have a built A body slant, I want to put into a 64 Plymouth B Body.
Are the engine mounts the same?
From your original post, I thought that you wanted to put the engine AND K-Member out of your A-Body into a B-Body.
If the B-Body already has a slant 6 K-Member in it, it is as simple as using the mounts and insulators from the B-Body engine and swapping them onto the good engine and it'll bolt right up.