headers vs manifolds and motor mounts

What is better exhaust manifolds or small tube headers? I have the manifolds right now and with swaping engines I may replace to headers if they are any better.

Also motor mounts for a 1972 Chevy, how do you get the things off is there a way to unscrew it direclty from the engine without removing the entie mount?

Headers are a nice addition although in some cases they make changing the plugs a real PITA. Motor mounts should have a long bolt running front to back that comes out. Once the motor is out you can remove the mount from the side of the block.

also between the engine mount and the engine there is a rubber filler, it is pretty worn so I am going to replace it. What is it? I do not know how to look for it at stores without knowing what it is called

The rubber you're seeing is part of the motor mount that's attached to the block. Go to your local parts store and ask to see a motor mount for your truck and you'll see what it looks like.