I need a little help from the engine experts here. I just replaced the camshaft in my 68 400 going to a more stock cam from the long duration one that came with the car. As a note, I also went from a Mallory electonic ignition to a stock distributor with points setup. When we installed the cam we set it up with the marks on the new timing chain set and everything worked out and we broke in the cam for about 30 minutes. However, we didn't degree the cam, just set it up as it came. The car has good low end power now, but when I coast at idle, there is some popping in the exhaust. I'm wondering if this is likely a result of retarded cam timing due to the exhaust valves staying open too long or something. I'm sure someone here has good experience with cam timing. I've checked the web and there are lots of articles on how to degree a cam, but not many about the symtoms if it's off. Any insight is greatly appreciated as always. I'll likely go back and degree the cam sometime. Thanks.
Good low end would be the result of a well installed cam - or even advanced - not retarded. Sounds like you have a timing problem. Check to be sure the vacuum advance is working on the carb, and that you hooked it up to a PORTED vacuum source, and not to a manifold vacuum source.
On the stock Pontiac engines, most were timed between 6 and 9 degrees, I would start at 9. Go from there. Your cam from the factory would be installed straight up, degreeing is not important on these cams.
