I just got one. 90 amp. I used the p/n for an 89 diplomat so that it would come with a v-belt pulley. To install it on my eddie headed 360 smallblock I had to do a bunch of stuff:

-take off the plastic back cover
-remove the brass standoff on the + connection and cut down the stud
-make a bracket to extend the outboard mount down (the stock bracket hits the big fan that is installed under the pulley. I used two pieces from the front and back to extend the mounting point about 4" down. I think the 'andy f' bracket has more circular roundness to come up from the bottom instead of over from the side)
-shave the front of the inboard mount about 1/8" to prevent the ceramic piece on the back from rubbing the head
-Install good ground wire and fat positive wire going straight to the battery (in addition to the stock + wire) to prevent ammeter/underdash meltdown

I did all these things last week, and fired her up and let her get warm. No problems, voltmeter reads 13 steady.

kevin in Philly