So for years I've used the Holley red deadheaded into the Mikuni at 4.5 psi. At this moment, I've got the same red Holley deadheaded into the Barry Grant 575 at about 7.0 psi, which is about all the red is good for.

Should I unplug and use the gas return line? Will that quieten the Holley red a bit?

Or should I leave well enough alone until/if I go to the Holley blue pump ?

 

Not unless you change to a return style fpr. Holly's fpr was not designed to be returned.

 

If your goal is the quiet it down then I believe it has the same mounting style as the carter pumps that are sold at Napas. They make a kit to quiet it down.

 

i have a 6psi pump and no return and just capped off the return line on the car. later on if and when i ever go FI, i'll need it.

 

yup, i've never found a need for it with a aftermarket carb setup either. if it works, use it.

 

If you ever go bigger on your pump and your oem return line is already there, definitely use it. As far as noise on the Holley, isolate the pump with black rubber sheet cut to sandwich fit between your pump and its retaining strap bracket. Also, make sure you have rubber bushings between the pump mount and your chassis sheet metal. Metal to metal contact has to be minimized as much as possible, and i am assuming your oem rock gaurd panels are still in place around your Holley pump.