77 Sub, my Qjet finally took a dump, so I ordered a rebuilt thru reputable mfg. 3 rebuilt units later & still junk. Got Holley, can’t get running ?

[MrHappy]

I have only ever run Holleys and I have never once ran a regulator with a mechanical pump, never even checked pressure, just set up the carbs and ran them….glad you got it worked out, this is why I don’t like “buddies” helping me out

My 72 3/4 ton pickup has original mechanical pump & I hooked it up directly with in-line filter to Holley with no regulator and it runs good. I don’t know what pressure it has & never checked it either. I’m gonna try the 77 with out it & see what happens. But now !! I’ve got lower radiator hose leaking!! Typically ya fix one thing & something else goes wrong ! So for now I gotta move this outta my garage & get another truck in. Thank You for input.

 

[MrHappy]

I had a mechanical pump that wouldn't stay below 7 psi. I had to regulate it. Only one ever.
I have been pleased with my Qjet from Sean Murphy Induction. Got it done over 10 years ago. He made it run well with my solid roller cam.
I have no recent experience with SMI though.

I wished I would’ve kept one of those Qjets I returned, there’s a Co. in Texas who builds them specifically for you and the way your going to use them. Darn it.

 

[MrHappy]

At one time a sbc pump was available with Bb Chevy diaphragm, I had to run one on hot 327 with a big holley on it. Engine ran out of fuel at the top end on a normal sbc pump.
I have a Jegs brand 80gph pump i tired on my burb before i went electric, normal is 40gph.

That’s something I’ve never got a grasp on, how to break say 40gph into psi ?

 

[Wes Harden]

Psi is a result of the plumbing restrictions to flow. Skinny many bends will have higher psi and lower gph. Wide and straight will be lower psi and more gph.

The exact same pump could have a wide psi range depending on how it plumbed.