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Discussion Starter · #1 ·
Hi everyone, There is a Carter #4070 pump mounted in my car right now, My new engine got dynoed to 371 Hp & 396 Ftlb of TQ, this pump gives out 72Gph at 6psi, Would this cover my needs, And should i run 3/8" or 1/2" fuel line? I guess it will be without a return line.

I also got a brand new blue holley, But i keep on reading so much negative about them..

Anyone?

Thank you..
 

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I would tend to think it would be a little on the shy side for the motor's fuel needs. I've got a holley 110gph in my 393 and it seems to do the trick...
I also only run a 5/16' fuel line from the pump to then tank and it doesn't seem to starve the motor at all???

Tom
 

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The needle valves in the carb, play an important role in this. The larger the needle valve the easier it is for the fuel pump to get fuel into the bowls....hence you can use the pump you have.

You should be using a .110 set of nedle valves if you are using a holley DBLPMP with your horsepower.

Why do you think your pump is too small? Does it loose RPMS, if you hold it above 6000 for any length of time of a few seconds or longer? If so, could be your pump or the needle valves are too small.
 

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If you used the carter on the dyno you should be fine. those are nice numbers for a 390. 3/8 line is fine with that power.
 

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Discussion Starter · #5 ·
Thanks for your answers!

I´m using a Holley 750cfm vaccum carb, Not a doublepumper.

Actually this carb seemed to be a bit "narrow", the engine was bulding up -2.4 in vaccum when it should be around -0.0 on high rpm´s.
We also had big troubles with the distributor (Mallory unilite), So with these two problems, i think the numbers are ok. I was hoping to reach 400 atleast with the Edelbrock performer RPM heads, .555 lift cam, roller rockers, notched cylinders etc.. But hey, It´s what it is.


Well back to the pump, i just wondered if the 72 gallons/hour would be enough, Because i have heard so much bad about the holley blue i also have. The engine has only been run with the carter before i built it all new and got it a bit tuned.

I think i´ll run 3/8" single line, no return.
 

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Discussion Starter · #6 ·
Dont mind, Installed the Holley pump today, I´ll keep the carter in the car as a backup in case the holley should retire.
 

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72 gph @ 6 psi would support 720 horsepower.
Well enough to feed your muscle. Also 5/16 line can handle upto 300 hp, 3/8 upto 500 hp. I ran the Holley blue for a little bit, Had to clean out often went to mallory comp 110 geroter design no rotor & vanes,
 
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