Are these the right size jets??
 

Procharged 502's, 6 lbs boost, heads ported.

Holly 750s

Jet sizes:

78 Main
4.5 power valve

96 secondary
power valve plugged

Does this sound right?

Have you looked at your plugs?

I haven't had a chance. Last time out we got stuck in a huge thunderstorm and on top of that when we got back to the ramp i discovered a fuel leak so I just loaded the boat and took it home. I have since been repairing the fuel tank and have not been able to run the boat.

When we were out the last time it "fell on it's face" at 4800 rpm. Last yr. before the carbs were rebuilt, it went 52-5300 rpm. So I think it is lean but as soon as it is back together I will be checking the plugs.

I ran a 9# pulley. 84 prim. 96 sec. and all 1/2 fuel lines on a 7.4.

I recomend start with 3 sizes larger than stock on jets with indexed power valves and 3.5 powervalves on both ends to start read plugs and go from there ,Ill index the power valves for free you need to do it !!!

Thanks Bobby. Ummmmm, what does it mean to index the power valves??