There are a couple guides. Here's how I did mine.
12SI from some 80's GM car. 9:00
According to
http://www.madelectrical.com/electri...elcoremy.shtml
12SI, 94 amp, at 9:00 (AC-DELCO # 321-269, Lester #7294-9) - Tell the auto parts counter person that “The alternator is for a 1985 Buick Riviera, 5.0L (307Y engine), with Heavy Duty options and Air Conditioning.”
You have 3 wires.
The big lug goes to the junction block with 8 or 10 gauge wire.
The left spade goes to the brown wire that previously went to your voltage regulator
The right spade goes to the junction block. This is a reference, so 16 or 18 gauge should be fine.
I also used a ground wire. There is a ground bolt on the case, I attached the wire to the block there the alt bracket attaches.
You can remove the rest of your voltage regulator wiring.
There are jumpers that allow you to leave your factory harness unmolested. I preferred the simplified wiring, heavier gauge wiring, cleaner look.
EDIT: Wanted to add that my alternator had a metric top bolt. 10 x 1.25? I had to grind the bracket for it to fit and be able to move.