When I dynoed Jeff hoekstras 509 MPI, we made a little over 600 hp with open headers and his stock gen 6 cool fuel. The pressure dropped about 4 or 5 psi on top form 40 or so to about 35/36. When we put mufflers on, it richened up slightlyso we leaned it back to the target afr that made most power and saw about 590 hp. Fuel pressure didnt drop quite as much. we then bolted a set of Eddie marine manifolds on with 02 bungs, it again richened up, we retuned it back to where it made best power which was 570 something IF I remember correctly. there was neglible pressure drop so around 570/580hp with BSFC of about .55 the factory efi pumped is close to maxed out. I know you went a different route now so this is irrelevant but I thought someone else might be curious, Smitty
I boosted the voltage to pump years ago on my Baja when I couldnt get enough fuel when making over a 1000 hp , that was a aeromotive eliminator 1115 pump

Thanks Smitty. Your notes on this had me questioning the pump to begin with.

I may be changing direction... Sniper EFI. I’m not sure the existing pump will work, and based on your previous notes, my thinking is that I’d need more of a margin of safety added in so now looking at other options. Same options as with the carb set-up but better pumps. I like the idea of using a fuel cooler, but running lines back to the tank isn’t that hard to do.