'68 firebird carb questions
First off i have a 68 350 4bbl firebird. The carb is a 670 cfm holley street avenger sitting on top of a edelbrock performer manifold and 1 inch four hole moroso carb spacer being supplied with a holley 110 gph mechanical fuel pump. My carb was backfiring for a couple of days kind of bad and was wondering if anyone thinks its possible that i blew out the powervalve? Also, i have the idle mixture screws set out about 3 3/4 out-- is this to far out? I am not sure if there is a such thing as turning the screws too far out. Lastly, my gas cap on the bird is not vented, should i replace it with a vented one?