The smoke is definitely not coming out of the tailpipe. I've let it sit then started it, warmed up and revved it and nothing has ever come out of the exhaust. I even had a friend follow behind me and he said the smoke definitely wasn't from the exhaust. It's all under the hood area. I really don't think it has a cam either. Just sounds like a crappy idle. I know for sure it has an exhaust leak and I'm wondering if the balancer is bad, I'll have to figure out how to check that. I'm pretty sure it has valve float too. I don't know what other rattling noise it could be at higher rpm? When I check the plugs what should I look for?