Here's a conversion I did using 1991 Chevy S10 parts in a Firebird. (the 4.3L stuff bolts right on a small block) $100 for the brackets, alternator, P/S pump, A/C compressor, etc.
The Pontiac came through with a Buick V6 in it from the factory. It was a TON less work converting to the serpentine set up because I already had the passenger side A/C compressor and driver's side alternator. I didn't have to change any wiring or make new A/C hoses. It all dropped into place and bolted up like it belonged there.