im not really sure as of right now. i was sure that both was off of a 71. the alt was the only style that would fit my braket. i didnt really get all to much done today though. but i found out that my floats are bad so im ordering some brass floats and reuseable bowl gaskets. but i would still like to trade carbs with someone though, maybe with some cash on top if someone has a blow threw carb they want to trade.