These questions are aweful rookie like.
New to this?
I believe you need to read a book or two.
How to rebuild and how to hit rod your small block MoPar would help you A LOT.
Cranks fit into the block.
The back of the crank is ether drilled for a manual trans or not.
If not drilled for a manual trans input shaft, have it machined.
The newly drilled pilot hole will need a bushing.
The manual trans input shaft needs that bushing.