If it's the original motor you'll need to do some research. If it's a later block, ('67 on?) the best conversion is to the regular GM alt.. Just go to a alt specialist and they'll know which one fits . Personally I would avoid the Bosch oem 'cause it's a POS. You need to modify the GM alt by boring out the bottom bracket hole so that it's large enoughto go around the bolt that you found to fit into the bolt hole on the front of the block. It's some kind of interference fit, so bolt length needs to be right ( or a few extra washers). I also had to mod the belt tension adj (extra section of sloted steel which I bolted onto the original one). Anyway, since then (5 yrs ago) I've never had a charging/starting problem, and it's easier to adjust the fan belt tension.
-- oh yeah, the wiring, just ask the alt guys, they'll know, basically there are 2 wires, one to + one and one to the amp light on the dash.


Disclaimer: be careful, work safely!!! If you have any doubts as to the safety of the work you are doing, consult a proffessional before you hurt yourself or others!!! I'm not a licensed mechanic, I have just been fixing stuff my whole life, patrick of