2005 Merc 40m mods for river racing

[cory]

Guys, got a 2005 Merc 40m 3 cylinder (about 1000cc). Runnin on a 14' 44" bottom semi-v aluminum boat. Boat weighs about 300# without me in it nor the motor (another 400#), set up for running fast with all my fishing crap pulled off. The motor has stock reeds, 60hp reed stops and 60 carbs. Rev limiter has been disconnected. A local prop shop shaved the leading edge??? of a Power Tech semi-cleaver 14" and it turns about 6000 rpm according to my Teleflex tach, consistently. GPS shows about 42 mph with a little porpoise. I have the motor up on a 4" setback plate. Prop shaft is running about 2" below bottom of boat. Trim tabs are set to neutral. On a cool day with a little tweaking, I can get about 200 more RPM and about 1 or 2 more mph.

My question is twofold.

What else could I do to the motor? I don't really plan on turning over 6500 or so. I want to cut the tuner and relieve the exhaust but don't really have an idea of where. I know a basic rule of thumb is 2 1/2 times the diameter of your exhaust port for the end of your diffuser cone. Does this apply to outboards as well? Do I need to go with Boyesen reeds? I know alot of guys add a little exhaust duration but I'd rather not cut on ports until it grenades.

For you Ron, what prop works well on these hulls? Most I've seen run anywhere from semi-cleavers to round ear Vengence style props. A few guys with some mods run full on Sport C cleavers. It would seem that I would want more transom lift to minimize porpoising, but some say I need to get the bow elevated? I am planning to send the lower unit to Bob's to get a nose cone installed. So the prop may see a little more surface in the future.

THanks to all and sorry for the big post!