Thoughts on Fuel Line Size

I run a -10 or 5/8 feed and return to the front of the car at 28-30 psi. The bypass regulator up front drops it down to a carb friendly 6 lbs. The trunk mounted fuel pump itself has a -8 bypass directly back to the tank too. Helps keep the 1 3/4 horsepower pump cooler at low fuel flows. It's feed by a -12 pick-up in a 30 gallon custom stainless, baffled tank that fits right into stock mounts of my 1970 E-body.

It feeds a 720 hp 493" sixpack, but it's pretty loud I spite of my attempts to get the sound down and out of the cockpit.

This winter, I'm going to switch over to the new Walboro OEM style in-tank high volume EFI pumps with a Radium Engineering surge tank ( the in-tank pump fills the surge tank and free fllows back to the main fuel tank at near "0" psi, but with very high volume) with another internal Walbro EFI pump inside the surge tank with bypass regulator mounted next to the it bypasses back to the surge tank to drop the pressure for the fuel feed to the front of the car to only 28-30 psi. The current bypass regulator up front is already seeing that pressure from my existing system and it can easily drop it down to a carb friendly 6 psi. It also bypasses the fuel back to the surge tank.

This system virtually eliminates any air induction into the pressure side of the fuel system even when the fuel level is low on a road course.

My current system can't do that. It's designed for straight line acceleration. It works very well for that though!