HOLLEY SUCKS!!!!!!!
It's called a blown power valve.
Like the good Dr.(Elusive) says, EDELBROCK is the choice. If you want to save a couple bucks, get a CARTER, which is basically the same. Ten years ago my best friend and I put a Carter 750 on his SB Chevy, whoooeee what a difference!
And for review:
HOLLEY SUCKS!!!!!!!
As for Barry Grant, never used one, don't know anyone who has, so no comment on the Demons.