Saturday, December 19th, 2009 AT 3:36 PM
I have a 302 block that has been hopped up with a big cam, AFR aluminum beade, highrise intake and all the goodies inside. The engine ran great untill my mechanic suggested I put a better carb on it. 650 Holly duel feed. Now when I accelerate heavily, especially in 3 rd and 4th, the engine backfires and breaks up. With no load on the engine and in netrual she responds perfectly. The timing is right on and the electrical all seems dialed in. Electric fule pump reads 5 pounds, new fuel filter too. I do not hear and vacume leaks. Can you help?

