Rough engine 1966 c20

[elliotweiland]

I just finished rewiring my c20 and fired it up for the first time since purchase. I installed a new distributor, coil, fuel filter, air cleaner, harmonic balancer, put fresh high grade oil, topped off the radiator, put new valve cover gaskets and rebuilt the stock 2bbl rochester. The truck idles quite high, maybe around 1500 rpms give or take (haven't hooked up the tach). I know that the exhaust is just about **** but I'm wondering if it could play this large of a role in the poor idle. I have fixed exhaust leaks on a few other cars and its made quite a bit of difference so I guess that might be it. Inside the cab there is a bang sound. Low and muffled but doesn't sound like a knock. I'd guess the exhaust has a lot to do with that. My question is what are all of the possible culprits that factor into this rough and high idle. Brakes aren't hooked up so I can't say how it runs at speed. Thanks for any help