This is what I have been doing in the past few days. The alternator is a high power cs144 unit. The brackets were a kit andyf sold years ago, modified to be more rigid. Previously the alternator was running on the same single v belt as the water pump.
I moved the alternator forward and added the serpentine pulley. The crank pulley is a March Performance # 6271, SBC short water pump serpentine pulley. I'm not sure if that particular application came stock with serpentine or not - I looked for a while but couldn't find any "flat" (no nose cone) 7" serpentine pulleys so I pulled the trigger and bought this piece from summit. I read on a past post here that the 3 bolt holes were same pattern as our balancers, the 3/8 holes.
Well, it wasn't quite. I could get 2 screws in, but not the third. Perhaps the machining on this pulley was off. I used one or two size up bits to make all the holes bigger. I also had to drill the smaller 5/16 hole pattern into it as that is how my adapter / 36 tooth gear setup was made for. I also had to move the sensor forward, which means I had to move the fan forward. The fan is maybe 3/4" away from the radiator - time to get an electric unit. The serpentine belt also hit the bottom of the stock single groove water pump pulley - the cone profile was too wide. What you see on the water pump now is a dual groove with AC water pump pulley, with the rear groove cut off. Had to do that - otherwise the rear groove would hit the top alternator arm since it had to be moved forward. I could have fabbed / modified the top bracket but I was under a time crunch.
