Helping a friend get some performance from his boat. He's got a Late model Bayliner 185 bowrider with a Mercury 4.3 liter V6 (looks like a Chev product with factory Merc mods) and I belive a Alpha I sterndrive currently running a four-blade 20 pitch Aluminum prop.

I haven't alot of experince with boats, but have built many skidoo and pick-up truck engines. My first thoughts are this thing needs some AIR. I think he needs to install a cold-air-intake to replace the stock restrictive underhood intake, does mercury or aftermarket make something?

Next we need to get some cool air under the hood as well, the stock under-hood-exaust-fan is a joke, where can we get vents that will let in air but no water? And a fan that moves some air?

And he wants to try a 23 or 24 pitch 3-blade prop for some speed, as the current 4-blade 20P is great for skinig, but "revs out" when Wide open.