When we were kids in the sixties, we would swap out our toilet bowl carbs for Holleys or AFBs. Our motors never ran right. We always knew V8 engines out of 1957 cars ran great, so we were on the look out for them. 1957 Fords were common. There were always one or two behind someone's house or in a field. (I grew up in the South). I remember buying compete running 1957 engines for $50. You could buy a whole car for $100.
We never knew why 57 YBlock engines ran so good until much later. The Loadamatic was one of the reasons the scruby's got the jump on us. Once Ford fixed that piece of junk, things changed. (Lemans 66-69)