Robert,
Sizing injectors based on anticipated power levels can be misleading. The idea of BSFC provides a wholesale correction for parasitic drag, pumping losses, power to drive the blower etc. Not surprisingly those numbers move around a fair amount depending on how the engine was built and who built it.
A far better way to estimate nozzle sizing is
The Fuel System Calculator. In stead of guessing at all the possible variables that will put a drag on the power output the calculator focuses exclusively on the engine's air consumption and the AFR you specify for the engine. if the safe AFR you want to run is 11.8 (suitable for non-oxygenated fuels) and you know your engine's using x amount of air, the air fuel ratio tells you how much fuel you need for that volume of air. Whether a portion of the power created by the combustion process is consumed in parasitic loss or not you know with absolute certainty that the air and fuel consumption is defined by the ratio of air to fuel you have commanded.
Check out the calculator here =>
Fuel System Calculator or in the TToC. The calculator is the fourth entry down, under the
Fuel System Section. There is a downloadable Windows and also a Mac version along with a pdf file that is the instructions. If you are running E-85 PM me there is a modification needed for E-85.
If you want to pursue the HP approach to injector sizing then this is how you would go about it;
Your injectors are 1065 cc/min injectors. At a maximum 80% duty cycle they would flow 1065 x 0.8 or 852cc's /min per injector. Your engine uses 8 injectors so the consumption would be 852 cc/min x 8 injectors or 6816 cc's/min of fuel. The specific gravity of gasoline varies depending on brand and octane but a good number to use is 0.755. That means 6816 cc's per hour weighs 6816 x 0.755 or 5.146 kg or 11.34 lbs/min of fuel consumption. Using an 11.8:1 AFR you need 133.8 lbs of air/min to burn the fuel. To make 100 hp you will need ~10 lbs/min of air. 133.8 lbs of air per minute will support a maximum of 1338 HP.
It is important to remember that the 1338 number does not account for pumping losses, parasitic friction loss or power to drive a roots blower. At 6500 rpm a 4.6 engine has about 85% mechanical efficiency - it looses 15% to parasitic drag. That drops the 1338 number to ~1137HP. Pull out another 100HP or so to drive a blower and you are at essentially 1000 HP. A water pump is worth 7.5 to 10 HP depending on the pump same thing for an alternator and we haven't even gotten to the other interesting power consumers or parasites like pumping losses yet. 1000HP is potentially an optimistic expectation depending ...
Do yourself a favor and use
The Fuel System Calculator. It will not only save you all the math it will give you the correct answer. If anyone intends to run a turbo instead of a PD blower just increase blower size until you get the boost number you intend to run with the turbo's. The injector size calculation will be correct for the boost.
Don't forget lower octane numbers require reduced timing that in turn reduces maximum brake torque and therefor horsepower.
Ed
p.s. The correct AFR for a fuel with 10% ethanol or other equivalent oxygenate is ~11.2:1.