Ok to start out I have a fresh rebuuilt 20/22r (less than 5000 miles) 82 22r block bored 0.03", remaned 20r head from and autoparts store, EB 261 cam, dual row timing chain, Federal Mogul pistons and rings, 20r intake, rebuilt 22r carb, 20r intake to 22r carb adapter, 2.5-5 gpm electric fuel pump, factory exhaust manifold into 2.5" exhaust no cat, cheapo raptor muffler.

Now onto the problem just recently I noticed (never checked before) that if I held my hand over the end of the exaust pipe while it was running it would puff my hand out and then all the sudden suck it back in real quick before it puffed it back out, it does it irregularly not any certian cylinder the truck runs fine. I have started smelling gas but I have no charcoal canister and my vent line for my tank is just sticking up under the hood. I adjusted my fuel mixture screw to 2.5 turns out when before I had it about three turns out and I also retarded my timing some( I had it set to get rid of the ping) and this seemed to help with the smell.

does any one know what could be the problem, I checked compression on all cylinders and they where all at 172 across the board, I adjusted the rocker arms to factory specs and it now has a little rattle. I will include a video of the sound of the exhaust.

[youtube]http://www.youtube.com/watch?v=DNj6i0Dz1AA&feature=share&list=UUr9uuENT5x DkDhkTlKXRRGg[/youtube]

 

could the cam be that out of time and still run without valves slapping the pistons?