Yes, a 6-71 can work on a 540 ci engine, IF......
you have a high enough static mechanical compression ratio and if you spin the blower fast enough.
Obviously you will be limited, but if you build the engine with around a 9.3:1 comp. ratio and run the boost at under 7 psi it will make plenty of...
I agree, a canned vertical turbine pump is probably your best bet. I'd also look real hard at all of your piping line losses, you may be able to get an increase in NPSHA by reducing line losses.
