This is a Holley 750CFM carb. It's what was used before fuel injection and computers. Little piss-ant millennials asking, ugh, what is THAT thing? Little bitches, this is what you fiddled with to make your car go fast and make girls panties drop! BITCH!
You put it on top of your goddamn 426 Hemi or your 396 Rat motor, tweaked all the damn adjustments, watched out for backfires thru the carb, got it adjusted just right, then went out and dragraced for a city block.
Ask anything about its operation and I'll answer.