[Big Block Bill]

I made my suggestion about trying a different Brand / Grade of fuel and possibly race gas assuming you had ruled out any vacuum leaks and the mixture was set correctly. Just holding your hand over the carb (trying to choke off the incoming air) while it is running can tell you if there is a vacuum leak or the mixture screws are not adjusted correctly if the RPM increases while you are doing that. Spraying carb cleaner around the carb base and intake gasket area can find a vacuum leak also if when you do the RPM increases.

An intake/vacuum leak can cause this smell you are talking about. Even if there is a vacuum leak it can run very well off idle. Once the engine is up to operating temperature, have you hooked up a vacuum gauge to manifold vacuum and adjusted each mixture screw until you have the highest vacuum reading and RPM? If not, that would be my first step.

I'm surely not questioning you're mechanical abilities but as I stated, I "Assumed" and we all know what that stands for. Just trying to help here.

As Snap On tools tag line went from years past, "Test, Don't Guess"

Let us know how you make out, Good Luck!

Bill