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Discussion Starter #1
I have the stock fuel pump in a 3 year old 350 GM crate motor with headers, 600 cfm carb and 9" x 3" K & N air cleaner. The car seems to breath real well and runs good, but it can seem slow to respond or sluggish at times. I just gave the car a tune-up; plugs, wires, distributor, fuel filter, thermastat, coolent change, oil and filter so I am guessing it's from lack of fuel, but I am just guessing. Would a moderate performance street fuel pump with pumping capacity of 110 gph at 6-7 psi make any significant difference? BTW, most of the fuel pumps in this catagory say no pressure regulator is required, is that really true? What is the psi on a stock fuel pump?

Lastly, any thoughts on making a change to a 750cfm carb form this engine?

Thanks in advance-
 

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A properly operating stock fuel pump should provide your engine with plenty of fuel. Have you monitored your fuel pressure?
 

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Discussion Starter #3
Interesting, I have not checked the fuel pressure, in what range should the fuel pressure be? and how would I go about doing that?

Thanks in advance-
 

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You are not normally gonna see a fuel pump causing 'slow response' or 'sluggishness' - they will usually cause the engine to cut out under high load or at higher operating RPM's.

I would first suggest a fuel pressure gauge as stated. Monitor the pressures to be sure they are not dropping off completely at high load/rpm.
Normal pressures will be in the 4~7 PSI range with stock type pumps.

Then I would have the distributor advance system checked and recurved to match you engine needs.
Most engines I run into with poor throttle response are tracable to the distributor advance system or to a carb. not tuned and jetted correctly.

Hope this helps;
John
 

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Put a gauge tap right in the line that goes to your carb and monitor it at that point. A typical pump will run 9 psi or so at idle then drop to 6-7 psi when you're underway. Pressures as low as 3# will work well on some carbs, like Q-jets.
 

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try not to go higher than 7 on stock holleys...the fuel will push past the needle and seat, causing a rich condition...
 
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