when I go from 509's to 540's ?? Everything else will be the same except bigger lb/hr injectors and a new tune. It will have the same heads, cam and boost level. They made 750 hp before at 8 psi at 5500 rpm. Max of 850 ft/lbs torque.

My guess +70 HP. Who's building the engines and tning them. Ateco has a dyno and can tune the EFI.

Your boost level may drop a bit with the extra cubes.I bet you see 100HP.My 540's @ 8psi 876HP.What cam and heads???

Crane 731 roller cam and lifters. Edelbrock aluminum heads with alot of port work done. I/E ratio 80 %

I'd be happy with 75hp more per motor. I know I will have to get a smaller pulley to get boost back to 8 lbs. I have also thought about going for a max of 6 lbs so as to not be as stressful on the motor and drives. If I can get 825 per motor at 6 psi I would be very happy. Also thinking about a custom grind cam from RMBuilder/Bob

If your motors were 502 ci and you go to 540 ci your gaining 7.5% more displacement,7.5% x 750hp=56 hp everything else being equal. Go with a custom ground cam matched to the flow #'s of your heads/intake and the gains will be more signifigant. Going from stock blocks to dart big m's you will have less cyl distortion/better ring seal also. You could easily make 900 plus hp with the right heads and cam,in 05 when I went from merlin heads to afr 315 cnc's and added 60 lb injectors I made 945 hp on the dyno with smallest pulleys,930 with everyday pulleys on pump gas (thru cmi's on crocketts dyno not turning any accesories using the more generous 60 degree sae correction factor that everyone uses except the oem's) and it still idled like a hp 500,Smitty

Why not go 572??? thats what I'm running ....about same price ,
I have 1078 hp @6000rpm 12#boost dart block, dart ci heads,
crane hyd cam......nothing fancy at 20psi over 1400hp!!

9.8 block maybe.

Solid roller or hydraulic?

Fastlane 40 See post #4

CNC-- 540 cubes is all that is in the budget !!! The next boat is going to have 572 blown engines that make at least 1200 each. This boat is not worth the effort.

75-85 Hp