The point was, you need to add something to your injector sizing to compensate for the unseen HP.

If you enter a correct BSFC to the injector sizing program, this (BSFC) accounts for that.

Sounds about right.

Okay. here is the thread he started on how much hp his ati took to run:

http://www.offshoreonly.com/forums/g...-hp-takes.html

Please remember though, do not add the larger BSFC SC's use and the extra hp it takes to spin the SC, this will be double dipping.

And how do you get the correct BSFC for every engine combo, different cubic inch, cams, heads, intakes ect ?

you using ignition retard? I would assume but didn't see it anywhere. Also did you post what exh valves got wiped out.

whats your timing at 5000rpm and 6lbs of boost?

also,you have any pics of your rigging in the boat?

http://i1225.photobucket.com/albums/...t/IMG_0073.jpg[/URL]

I didn't build these motors originally so never had the luxury to dyno them. The valves are manley extreme duty inconel. I'm running wide band 02 sensors but I belive they are in closed loop right now. Also have pyrometers on cyl 7 in each motor. These are crank trigger distributor less and timing is controlled by the ecu. I have print outs from the initial tune showing good AFR throughout the whole rpm range.

BUP checked my injectors and they were super clean, flowed well and we're even. He figured they were either too small or my tune is bad.

Its general knowledge that a typical BBC is around .48 to .52 bsfc, I saw .52 to .55 turning m-3 procharger past its rating, IF OP's claim of 72lb injectors is correct simple math tells us:
72lb X 8 = 576LBS per hr, erroing on conservative side lets say motor is at .60 bsfc, the injectors would support 960 hp at 3 bar/43.5 psi. 80% of that is 768 hp, at .55 would be more like 800 hp and thats still at 80%,, at 50 psi those injectors become 77lb injectors which will support 820 hp at .60 bsfc and 80% duty cycle.
We also know OP is running 5-6 psi of boost, if his motors making 600 hp on its own at 7.35 lbs of boost it would use 900 hp worth of fuel and after using 50hp or so to turn blower net him 850 hp, IF motor makes 650 hp the 6 psi of boost will only get a 265 hp gain MINUS what it takes to turn the blower yielding about 850 hp.