I would like to keep cruise around 2700 rpm. I would like to be able to run hard and be reliable.
As far as an intake, a single plane with an 800 or 850 Holley if this will work. I know that running such a tall impeller will probably leave some mph on the table but a true 550 horsepower should give some good mph numbers in a fairly light 19 foot boat.
Been there done that many yrs ago, if I could do it over again I'd take tha mph up top and give up alittle on the cruise side.
It's a balancing act,
Years ago we ( brother and I) had a stought roller cam 472" Ford in the CP with a AA impeller. Engine broke because of abuse of the little button on the steering wheel, replaced that engine with a nearly stock 460, that 460 damn near used twice the fuel of the more powerful engine. It didn't have the power to turn the impeller so it took more throttle effort and used more gas.
I don't think I see 2,700 rpm being a realistic cruise rpm, the impeller is only going to move so much water. I've had a 9.25" AA it pulled like a AAA the 565" turned that impeller 5,200 and the boat ran 92-93 mph and 102 at 6,200 on the Nos. I wish I'd have let the engine rev out to 5,800 with that impeller. That pitch impeller is no longer made and it was the most efficeint impeller I ever had ( mph/rpm).
I don't cruise the CP as most people run there boats. Most people cruise at 3,000-3,200 kind of lugging the boat along I run my boat fully loaded up river 12-14 miles at 3,800-4,100 at 50+/- mph on top of the water with far less drag. It doesn't use anymore gas until the secondaries kick in.
I think an 850 carb might be a bit small for your engine. Here's another thing on the carb, since '93 the 565 has had the same 1,050 Holley Barry Grant carb. First the engine was 780hp, then 855 hp and now 935 hp the same carb with progressive linkage, the secondaries didn't open until 4,000 +/- depending on the laod in the boat. Last year I got a 1,200 cfm Pro-System carb with soft-progressive linkage (secondaries open sooner). Patrick told me because of the way the carb is balanced it won't use anymore fuel than the other carb, as of yet I'm not sure about that.
I can't write you all that I've picked-up since '89 trying to balance cruise rpm with performance, but I agree with what Filucky stated about giving up a 100 or 200 rpm in cruise and picking it up on the top end. I'd let the engine rev out a bit more.
Do you plan on putting this engine on the dyno?
More later but I have to go for now.
G-
Jon