LT1driver

big block or small block with hipo factory carb motors...thanks.

gkull

I'm not a high pressure fan. But something up around 9 psi I have seen carbs develop leaks when dumb drag racers turn up the psi thinking that they will go faster

I'm a thinker. So 20 years ago I'm driving my double pumper vette and it started sputtering. The needle and seat wore out and stuck open so I was thinking about a cure. I reasoned that why not just run less pressure and use bigger diameter alky titanium needle and seats. I never had a problem running sub 5 or even 4psi with stock return type mechanical pumps

SH-60B

6 psi

fishslayer143

7 psi and above will overpower needle and seat in most applications, causing flooding after WOT bursts

F22

Agree on 6 PSI, maximum for a regular hipo street motor. I'd also add, that it's worth the $100 or so, to get the Aeromotive fuel pressure regulator. I've personally seen three of the cheapie $30 Holley FPR's fail (including mine) that went bad, leaving you stranded.

https://www.summitracing.com/parts/aei-13201/overview/

And the gauge as well:

https://www.summitracing.com/parts/aei-15632/overview/

MotorHead

4-6 psi.

MelWff

your getting different numbers because you are vague on the carburetors. Quadrajets run lower fuel pressure than Holleys and their clones.

gkull

My original Demon 830 carb had .097 needle and seats. I went to .150 titanium and they are still working today. years later I was talking to a NASCAR carb man and he told me that in the never ending quest for more power that they had come up with using big needle and seats which causes less fuel aeration.

Now it seems that the majority sold are bigger

https://www.summitracing.com/parts/hly-6-521/overview/

https://www.summitracing.com/parts/h...15-2/overview/

7T1vette

The 'engine' doesn't care about fuel pressure; the carburetor does. And different types are capable of handling somewhat different fuel pressures.

But, for most, 5 psi is a 'safe' working pressure. Over 7 psi is "not good" for many of them. {Not sure if this ambiguous answer is of any help for you....}