it's running rich, but the blower is probably toying with that carb. the timing is whatever you have it set at, being a blower motor, it could quite possibly be retarded, or set at the Chevy SBC base timing ( not shure what that is ). you probably need to ajust jets and metering rods in the carb, but the carb is what is doing it to you. or advance the timing a little and run higher octane than you are, and try that.