Hi there Widetrack and welcome ! Both units are dual main air bleeds 800 cfm units. Both very good starting points. The 79 is a Pontiac and the 76 is a Buick.
I personally built a 17059272 myself for my girlfriend's 326 Firebird. Runs like a champ. I've added idle air by pass because it did not have any from the factory, no big deal. I think, not sure, that there is no large vacuum port in the front, those 301 pontiac engines came with a spacer so make sure it can be made to work with your set up.
Frank.