I have a mechanical Holley fuel pump feeding a 750 double pumper Holley on my 454 bbc. I have an inline gauge on the fuel rail and at idle it reads 10-12 psi. Isn't it supposed to be more like 6-7 psi? I won't idle and I'm assuming this is why. Too much pressure. Should I put a fuel pressure regulator on it? And if so which one?
A brand new needle and seat might have held that pressure. Same goes for the o-rings on the needle assembly. But its too much pressure regardless if it worked or not.
You don't need a some high dollar reg for a single 750. The Holley 3/8 reg is all you need and its much cheaper, and it a damn good regulator. LINK: Holley reg.