Im running a 509 500 hp in my 260 fx and turning a 25 pitch prop 1.5 to 1 brovo drive, 4000 rpm cruising speed is 55 mph real calm ride in rough water with that deep hull, at wot i can only turn 5100 rpm and run 71 mph. How can I go faster with out using a blower? my 502 is 30 over, I have merlin comp 320 heads, Dart intake, and a 850 double pumper carb, roller cam and rockers, and all msd ignition, stainless marine Headers. any Suggestions?????????????????? besides a blower

What RPM rev limiter chip are you using in the MSD? Any chance you are bumping it?

Aren't Awesome's cats??? If so, I'd guess your motor is not making anywhere near the power you think it is or you have setup issues.

My slow 24' Vee hull is going 78 with only 425HP.

What are the cam specs? With those heads and intake I suspect your peak HP is in the 5600-5800 RPM range, obviously depending on what cam you have. If this is true you are way over propped and leaving 50 or more HP untapped.

Get the merlin heads ported or buy better heads,they flow near stock numbers untouched,especially on the exhaust side,Smitty