Popping sound in headers

You could be right about no exhaust leaks. The gaskets that are available now are a lot better than they were 30 years ago. Seemed like we could never keep header gaskets sealed, they were always burning through.
If you're releasing the choke as soon as you say then it's very possible that the engine is just mis-firing because it's running lean when it's cold. If everything smooths out after it's warm there's probably not a problem. Does the car have an automatic or a manual trans? If it's an automatic trans and it idles smoothly when warmed up & in gear it probably has a pretty mild cam. This is based on what I know of cams from MANY years ago. Cam science has advanced an unbelievable amount since the last time I messed with a serious street motor (Hopefully I'll start "messing" again in the near future).


:burnout: