Fuel Tank Return Line

[Mike I]

Bob,
As long as we're on the subject, I'd like to pick your brain as well (or anyone else who can help). I'm running a Holley 802 Max Pressure "blue" pump (factory set at 14 psi) with 3/8" ID fuel lines, into a Holley standard pressure regulator (range of 1 to 4 psi) set @ 3 psi for use with Weber IDFs. The regulator is mounted directly to the firewall with each outlet feeding one bank of carbs and I can attest to Steve's concern for a "dead headed" regulator causing premature pump failure since I can readily hear and feel the pump straining against the reduction in flow, especially at idle when flow is at its lowest. I know I can isolate some of the vibration and noise with rubber between the regulator and the firewall, but that won't eliminate the strain on the pump. I probably need to talk to the Holley Tech people about this, but I thought I'd check here first since the question has already been asked. I'm considering switching to the standard pressure pump, which is factory set at only 7 psi, to lessen the pressure differential. If I were to tee in a "restrictor" return line (smaller than 3/8" ID) between the pump and regulator, and plumb it into the fuel filler breather line to be returned to the tank, would that effectively work like a pressure relief? If that will work, how small of an ID would give me the pressure reduction I'm looking for? I'm sure there's a calculation that will tell me that. Any advice you can give me will be appreciated. Thanks.

Mike