Fuel Line Choice and size

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FDNY340

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Good evening all. Plugging away on my duster and getting to the fuel line and Carb combo.
Using a Magna Fuel Quick Star 300 pump which comes with #10 fittings. Not sure if #10 is overkill for fuel line though. Motor is a 340 with 10:1 w2 with a strip Dominator, 8 inch converter with a brake and 456's. Some street some track. Motor was dynoed with an old 750 DP and a new QF750 because I ran the Holley prior build and my builder had the QF. Both pulled just about the same at 500 plus HP. What are your thoughts on fuel line size and Carb selection?? Thanks all and enjoy the holidays!!!
 
I believe 5/8 fuel line will be plenty. Or you could just jump to schedule 40.
 
I upgraded from stock 5/16 to 3/8 hard line. Provisions for 5/16 return on restoration.

292/509 Purple 383HP with full stock exhaust.

Now running a newer off the shelf simple 800AVS Eddy. "Slightly" tuned with factory HP mechanical pump on a TM-6 Eddy single plane intake.

Removed the 4.56 for 3.55! Using a custom 9" loose Convertor. No starvation at all!

Needed much more when running the 2 stage NOS! I had run twin Holley Blue pumps with 750DP on 3/8 soft line!
 
I mean seriously, a -10 fuel line. That might as well be a reserve tank. lol
 
Stock fuel tank, or fuel cell?
My cell came with two -8 outlets, and I used to run both into a tee before the pump. New setup is a single -10 to the pump, -8 out to the filter, -8 connector to a 1/2 aluminum fuel line (probably overkill) -8 connector to the regulator, two -6 to the carb bowls, (or two -8 when I run the crossram.)
I run dead-headed, but a return should be at least as large as the supply line.
I have to replace a carlength of -6 braided line on my other car (previous owner) cause the rubber deteriorated, and now leaks like a sieve. Gonna use aluminum line on this one too.
 
I hope you are using a bypass regulator with that pump. Nothing wrong with #10 line, but the return should be the same size as the pressure line.
 
Running #8 line from fuel cell to regulator ....then #6 line to carb....using 140 gph fuel pump pushing E85.
 
33IMP said:
Stock fuel tank, or fuel cell?
My cell came with two -8 outlets, and I used to run both into a tee before the pump. New setup is a single -10 to the pump, -8 out to the filter, -8 connector to a 1/2 aluminum fuel line (probably overkill) -8 connector to the regulator, two -6 to the carb bowls, (or two -8 when I run the crossram.)

Looking like I will be similar. 1-10 from cell to pump and 8 rest of the way. Thanks for the detailed response
Click to expand...
 
Rat Bastid said:
It depends on the pump.
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mrf-mp-4810_w.jpg
 
Size does matter. Go Big or go Home. I vote #12. For future upgrades down the road. :)
 
That is big, bad boy pump. Whatever you do, don't restrict the inlet side. Dash ten at least, and the right micron filter if between the cell and pump.
 
Rat Bastid said:
How would a 3/8 inlet line not restrict that pump?
Click to expand...
I was thinking cheap, if he has an engine that needs more than 120 gph, ( 2 gallons a minute) or (2) (55+ gallons drums worth an hour), then by all means, go 1/2 inch
 
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Brooks James said:
I was thinking cheap, if he has an engine that needs more than 120 gph, ( 2 gallons a minute) or (2) (55+ gallons drums worth an hour), then by all means, go 1/2 inch
Click to expand...
Well, if that's his stuff in the pic, he's got about $700 worth of pump,regulator, fittings, and relays.
And a 300 gph pump.
 
That is a hell of a pump for a 750 cfm even at wot.
A 3/8" feed with a 1/4" return and a smaller pump is plenty to feed a 750.
 
I believe o.p. has the magnaflow already, we are just trying to make sure it works efficiently and has a long life. FDNY340, you might want to look into a fuel pump controller that regulates voltage to the pump, depending on demand. It will help with a long life for that bad boy pump.
And yes, he likely has a lot more pump than he needs. I have been high tens with a 150, high nines with a 250 Mallory (LOVE that pump, but today's price for it is insane!) and the 250 was more than it needed.
 
You can’t get push rods that are too stiff, too much ignition or too big a fuel pump. Those Holley pumps are pretty much bargain basement stuff. The OP bought nice stuff. It needs a #10 line to feed it. Then he needs to figure out how much fuel he will be returning at WOT and size the return line accordingly. Or he can use a 10 line for the return and be done with it.
 
Magnafuel says a 10 feed line and an 8 return. With an 8 vent. That’s exactly what I would do except I may use a 10 vent.
 
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