We have a Holley spreadbore 670 cfm. I believe the guy we bought the car from put this carb on when he rebuilt the engine. He did give us the original Q-jet that was on there. I do not know if he switched the manifold or not. We have been having some tuning problems with the Holley so we were going to purchase a new Q-jet from Edelbrock would that carb bolt right on a stock big block manifold, or would we need a new manifold? Thanks in advance.