I tried to do a search and didn't come up with much on this....

I'm running a Holley 650 DP on a GM Performance HO Deluxe crate engine (Vortec heads). I have a mechanical fuel pump that the shop is claiming doesn't put out enough fuel pressure. Now I've read that the Edelbrock carbs don't like fuel pressure about 5.5 psi. What ballpark number am I looking for with the Holley?

6 to 6.5 PSI is what we run on the dyno for Holley carbs.

What pressure did they say the pump was putting out?

That's the part I don't remember. They were going to call me back, but I haven't heard anything more yet.

And the car IS being dyno-tuned....

Thanks for the prompt reply, Rick!

I'm sure the shop knows this but it certainly could be a volume related issue. If pressure falls as RPM increases on the dyno there is some sort of restriction. Either fuel lines are too small or the pump is too small. OR...filters are dirty.

I think your fuel pressure is fine.

You may be low on the fuel volume with a stock pump at WOT through all of the gears

Thanks for the quick responses and information, guys! The pressure was around 7 but when they'd get on it, it was dropping below 5. They had a hard time getting the air/fuel ratio to fatten up. Ended up putting on a Holley 110 fuel pump and replacing the fuel filter as well. The old one looked fine - but they threw it in for free, so I'm not complaining. And had to jet the secondaries up 10 sizes - from a 73 to an 82.

New numbers - 291 HP and 343 torque at the rear wheels. I didn't think that was bad considering the engine is rated at 330 at the flywheel.

Come on track day, lol!

Rick you have a pm