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My 396 runs out of gas in high RPM's... It doesnt ALWAYS happen, but about 50% of the time if I really nail it the engine will start to die up around 5,000 RPM, sometimes even lower than that. I've replaced the in-line fuel filter, and the electric fuel pump is brand new. The fuel pump is located on the right wheel well. I have been told by some people electric pumps like to be close to the fuel tank... Could this be my problem? I am not quite sure off hand what the gallons per hour rating is on my pump. What would be a good rating for a 400HP 396 with a Holley 750 D.P. carb?

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Ryan, What size is your fuel line? you may need to upgrade to maybe a 1/2 inch line versus a 3/8. Not to knowledgable on electric pumps, but it could be possible it is bad, but try the easier stuff first. My Chevelle did the same thing with a mechanical pump so i went and got a new one and it stopped it! Hope this helps!
 
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Most electric pumps are "pusher" pumps, so they like to be near the fuel source, in the back near the tank. Also make sure that any rubber line you may be using is "fuel" rated and not cheesie junk non fuel hose that will go soft and squishy and flaten out under load.

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Wally
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67 malibu
 

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Maybe you have some crud in the tank that is clogging the "sock" that picks up the fuel in the tank. The crud can move around a bit and create a variable situation for you. Do not remove the sock; remove the crud. The sock is a good thing for picking up the last bit of fuel from the bottom of the tank.
 

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Ryan, there are a couple of things to look at.

Is the pump inlet side lower than the outlet of the tank? The pump relies on gravity to get the fuel to the pump.

Is the tank properly vented?

You mentioned an inline fuel filter. With aftermarket electric pumps the only fuel filter should be between the tank and the pump and capable of flowing at least what the pump can. Take out the carb filter if you have one.

What type of ignition are you running? A weak ignition system will always let you down above 5000 RPM. Good luck...MK
 

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Yes electric pumps need to be in the back below the fuel level. I have seen electric pumps work up front if they are mounted down low so the fuel can get to it, but they still do not work great up there. I run an Edelbrock mechanical pump with no problems.
 

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I put a red holley fuel pump on my 69 what a mistake I should have bought the blue one. So an old drag racer that used to have a factory backed hate to say it Mopar 65 Plymouth with a Hemi told me to just run my mechanical fuel pump also along with the red one and it ran fine after 5000rpms. The Red Holley fuel pump could not get enough fuel on acceleration. It was easy enough to hook up the mechanical pump inline, I also put a regulator in front of the carb.
 

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Just another thought about electric fuel pumps being gravity fed...siphoning gas up and out of the tank is forcing all electric pumps to work REALLY hard to get the fuel to the front.

I managed to ruin a set of brushes on a new Mallory Comp 140 pump. I too had the electric fuel pump mounted below the fuel tank but the fact that it was having to siphon gas up and out of the gas tank is what prematurely killed the electric motor brushes. Fortunately, Mallory sells replacement brushes for cheap!

My solution was to go with a lightweight 16 gallon RCI fuel cell (flat bottom - no sump)mounted in the trunk. You can also drop the gas tank and have a shop weld in a bottom sump to the stock gas tank. Jeg's sells them for around $50, I think. Either way, your fuel pump will thank you because now it is truly gravity fed. Hope this helps!

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70' Malibu - 383 'Dental Gas' Inhaling Stroker! Gold Member #39
Chevellz Alwayz!
 
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