I'm looking for a 100-amp alternator. I find summit's 100amp alternator then I find out it's "designed" for 1973-86 GM engines. Then I find powermaster has a 100amp alternator but it doesn't say what it's designed for. Does it matter?

Magnum has an 80amp alternator designed for 1972-89 GM.

I'm looking more towards the Powermaster alternator but it doesn't say what it's designed for. (As I asked before) does that/should that matter?

 

stock alternater is 100 amp, just get a direct replacement