I just bought a American Offshore 2600 1997 502 mag mpi.The boat runs 78- 80 mph. I would like to see 90 -95 mph.What can I do ? exhaust , cam, heads. Prop is a hydromotive 15.4 23p. rpm 4800-5000, also what is the max rpm of a 502 mag.

HEY RIVERBOATER ,THATS EASY HOW MUCH DO YOU WANNA SPEND...ITS ALL ABOUT THE BENJAMINS-THAT HAS THE MOST DIRECT BEARING ON SPEED...WHATS THE BUDGET....

I believe the red line is 5200. I don't know what the limiter is set at though.

Because you are looking for 100hp, you have a couple of choices. I think that a cam and head change with some decent manifolds would do the trick. You could also consider sticking with your existing combo and adding a supercharger.

You could also potentially find some more speed in your combo. What are your slip numbers and x-dim?

Limiter is set at 5050. To get an additional 15+ MPH the easiest way is to install a Supercharger. I recommend the Whipple. Not a bad idea to upgrade the valve train with roller rockers and inconel exhause valves. Money is always the limiting factor.

Aluminum heads set up for hyd. roller and necessary blower mods. Do a cam change to a hyd. roller blower grind then go with some forced induction such as Wipple or a B & M 420. I would think 700 plus HP could easily be tapped out of that type of combo and the aluminum heads will help keep it on pump gas. Probably looking at $10,000 or so. The other option would be to make your 502 a 540. I know MIKEHTMSR24, KAAMA, and 26SCARAB are all getting nearly 700 HP naturally aspirated out of their 540 motors on pump gas. Either way you are looking at spending a few bucks to get 15 MPH. Good luck!

That's on the dyno. Take 30 hp off for the drive, another 10 to 20 from dyno headers to marine headers, motor assy. 10 hp, lost 20 hp by spinning motor to 5300 instead of (5700 on dyno). So I am about a true 600 to 625 hp at the prop.
610 - 415 = 195 hp. Cost way up their.
I like my N/A motor but superchargers aren't a bad chose either. Either way do it right the first time. Spend the money. If ya can't do it right wait till ya can

riverboater;

you need a legitimate 200hp to pick up the speed you are looking for. In my opinion money spent on good set of heads will pay you the best dividends. A set of dart pro 1 345's would be a good starting point. With a hyd roller cam you should be able to turn 5800 r's with the 502mag.