Fuel pressure is around 38psi ? at the rails on EFI. THat will change depending how much pwr you need to make. I have heard of using the stock carb. fuel line for the return line on an efi application, but I think thats hack. I would just run a return line when you install the new feed line.
A forum community dedicated to Mercury Cougar owners and enthusiasts. Come join the discussion about restoration, performance, modifications, classifieds, troubleshooting, maintenance, and more!