Like Ralph said, try to set you timing at about 36 total than see what it is at idle. Carb should be fine if it now flows 780cfm , but what intake are you running ? If its the basic Edl Performer that might be a problem. I've heard the factory cast iron marine ( CJ ) intake flows better than the Performer. You might want to look at a Performer RPM or a Weiland Stealth intake, both good intakes.
