picking parts for my 302

[bmxmon]

I bought a 79 302 awhile ago. Its stock, right now. I am planning on hopping it up a bit, especially since its easier with it out of the car. I have some questions. It came with a HEI (HEI, right?? three wire) distributor, but im thinking about switching it to a single wire one. Does the HEI just plug into a box, and where can i get this box. The reason i wanted to go to single wire was because im confused by the HEI. Second, what is all different between the earlier 302's and mine. I have found that the water pump seems to be different, looking through product catalogs. I am also confused about the camshaft. I am planning on getting a new one, for a little more power. What kind of camshaft do i get, a mechanical, hydraulic, flat tappet, what does this all mean??? And when swapping out cams, what needs to be changed?? Do i just put a new cam and lifters in, then can i leave the push rods alone?? Thanks for any help.