If timing is right and popping in exhaust...

[Banjo]

does this mean running lean? I've got open headers on 1 car while I get it ready for paint/exhaust and noticed yesterday no matter how many times I tried to set the timing when I'd rev it, the thing would pop through exhaust. Not a complete backfire like a gun, but a pop, and it'd only happen when it'd be a quick rev and complete let off. Seems I've read that means it's running lean???

[hazelnut]

this is what it sounds like to me,Ive got a ol 4X4 that i use for hunting and it was poping through the exhaust when i would hold the RPMs up,its a 302 2v and i put a good carb and new gaskets on it and now it runs like a champ.the old carb base gaskets were leaking and leaning it out and that was what was causing my poping on mine.

[fomocoguy]

I wouldn't worry about it until you put exhaust on it. Open headers will make all sorts of crazy sounds, plus it's not going to run correctly until you have complete exhaust on it. If the gaskets are leaking it's probably sucking air in at the leaks, but you won't be able to hear them until the exhaust is done.