if you put a overdrive puylley on a Alternator with it put out more power?

Well, Lets just say that from what I have found the difference between a 180amp alt and a 200 amp alt (which I have) is pulley size. Found this out a while back when I went to install it. So I would say a smaller pulley will make more power, but will also probably wear it faster (to be expected though).

interesting i amp getting a 180amp custom built i wonder how they are going to do it with a pulley or internals or a combo of both

It will be both. It has to be.