I'm about to buy a 2nd gen alternator and fuse box and all I know is that it's a N/A (not turbo) 86-88 part. Were the various 7 models (GTX, GTU, ...) stocked with different alternators, perhaps on the turbo models or anything like that?

 

The s4 alternator your getting is plug n play with a FB car. the turbo alts have 80 amps im pretty sure and the s4 na has 70.

 

S4 is directly compatible.

S5 requires constant power instead of key power to one of the terminals(see diagram). If you don not make this wiring change you will experence a 1A draw on the battery when the car is off.

 

This is what i was looking for but could not confirm through my search. I've read that there is only the 70 vs 80 difference when going from 86-88 (70amp) to the 89-91? (80amp). Can anyone confirm this?

 

I list the differences in this thread:

https://www.rx7club.com/1st-gen-archive-71/electrical-2nd-gen-alt-1st-gen-388262/

Search seems broken, so I had to dig for it.