I did a stock GM upgrade to my 85 Chevy truck......using a serpentine from a Vortec (96 to 2001) truck belt system. Some things that I found were:
1. Of course, the alternator, A/C compressor, PS pump and AIR pump are different than the old V belt stuff. The belt tension is controlled by the idler "pulley" instead of moving the alternator.
2. I cut the long bracket to eliminate the AIR system which I didn't need.
3. The serpentine water pump rotates the opposite direction from the V belt pump.
4. The FAN blades must match the water pump direction.....otherwise, you have a real mystery problem since the air flows backwards and comes out the radiator if you use a V belt fan blade.
5. Your heads may not have the correct hole locations for your brackets
6. There are no different holes for the block, I used a 1980ish block with no problems.
7. System results in a MUCH quieter engine even when using a thermostatic fan.
Would I recommend it? Certainly. The change isn't cheap but a lot of the aftermarket stuff is authentic crap.