85 firebird with v6, and install a 350 small block

Hi, i got a 85 Pontiac firebird, i got the car from a buddy, and he bought it without a engine, but he says that it came with a v6. I got a 350 small block in the shop. I want to know wat i would have to do to get this car ready to go with this engine. But also the person that had it before went along and cut all the wire harness and stuff, and i want to know wat i will need to do to get the wireing to match the new engine connected? PLEASE help me out, because i dont want this engine going to waste, and he was originaly was sellin the engine, but said he will throw in the car. So i mise well take advantage of it, and figure out how to get the engine in and ready to go! ya see! thanks kyle