Crate motors used the 509 hyd cam which is an okay cam if you know how to tune around it. It has a bunch of overlap though which makes it a pain when combined with low compression and a 1.560 carb. That was the standard "street racer" combo back in the 70's and a lot of those cars ran like poo.

If the guy knew how to clean up the idle circuit it would work okay but not a lot of people knew how to do that 30 years ago. (no billet metering blocks back then) The other crutch would be 4.88 rear gear and/or a bunch of initial advance.