Fuel pressure gauge

[Sparky]

UPDATE I installed a return line. It now hold 2.5 psi all the time. I don't really understand why the return line is needed, but it works. Thanks for everyone's help.

Could you tell us exactly which make/model regulator you're using? I'm getting ready to plumb up my system and Holley support was pretty sure no return lines were needed (with 12-804, which looks the same as the discontinued Inglese NG1081 Mark recommends in the Idf tuning guide).

[gtlotus]

I've tired different ones to make it work, but now I'm using the 12-804. I used this one before I had a return line but it would not hold a steady 2.5 psi. I've been working on cars of different types for over 55 years and have never had to use a return line before. But it works.

Gene

[Sparky]

Where did you end up putting the return line and what sort of restrictor did you use? Also I'm assuming you stuck with a ~9psi pump and new hoses from the front to the back? Are you still using the hard lines, or have you bypassed or replaced them?

[gtlotus]

I feed the carbs from the middle and the return line comes off the front carb. I make the re-stricter using a 135 weber main jet and a 5/16 barb
coupling. I'm using the holly blue 14 psi pump, new 5/16 rubber supply line and the return line that came on the car.