Thread: Fuel pump inlet size versus fuel line size is confussing me!!!

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....This is confussing me! I am planning on running 1/2" fuel line {which by my understanding is -10 AN?} so I will purchace -10 AN line. But most fuel pumps have an inlet/outlet of 3/8" NPT. A few pumps have 1/2" inlet/outlet. I am concidering running with 1/2 " inlet/outlet. So why would you run 1/2" {-10 AN} line and then go down to 3/8" to get into the pump? Doesn't this restrick the fuel flow? There is a better selection of pumps with the 3/8" in/out, I would rather pick one of these but this concerns me..... Please explain this to me! Bill

Originally posted by billlsbird
....This is confussing me! I am planning on running 1/2" fuel line {which by my understanding is -10 AN?} so I will purchace -10 AN line. But most fuel pumps have an inlet/outlet of 3/8" NPT. A few pumps have 1/2" inlet/outlet. I am concidering running with 1/2 " inlet/outlet. So why would you run 1/2" {-10 AN} line and then go down to 3/8" to get into the pump? Doesn't this restrick the fuel flow? There is a better selection of pumps with the 3/8" in/out, I would rather pick one of these but this concerns me..... Please explain this to me! Bill

its really no need to put a #10 line on a 3/8 fitting. they say if you have a 3/8 pump, dont use a line smaller than #6, i've just all ways run one size bigger than the pump size, wheather it helps or not i dont know. if you think the #6 is not big enough then you need to get a bigger pump inlet/outlet. kitz is probably about right, but it looks small.

To start with AN fittings are measured in 16ths. A #1 would be 1/16th, a #2 would be 2/16ths or 1/8. A ½ inch line would be #8.
It is true that most pumps come with a 3/8 in and outlet but they pump the advertised volume.
What most people do is run a #8 from the tank to the pump, this keeps the pump from starving for gas, that run a #6 or an #8 from the pump to the carb or regulator.

Most who run 1/2 inch (8 AN) to the carb run 10 AN to the pump and also run a 10 AN return line from the regulator.

Keep in mind that a first class fuel system like this matched with a top notch pump and stainless braided lines and AN fittings is gonna run you more than $1k. IMO unless you are running a supercharged big block or natural at 700 HP+ or Nitrous, you probably don't need all this. A well designed 6 AN system is still gonna cost you $400+.

My basis is a '68 427 Vette, built to 450 HP and using stock 3/8 fuel system and Holley mechanical pump. No fuel problems at all, fuel system cost $150.

Good Luck, Kitz

Here's the pump from Aeromotive....


A1000 Fuel Pump, P/N 11101

For fuel injected engines:
up to 1100 HP - naturally aspirated
up to 800 HP - forced air induction

For carbureted engines:
up to 1300 HP - naturally aspirated
up to 1100 HP - forced air induction

Flows 600 lbs. per hour @ 13.5 Volts and 45 PSI.
"Features -10 AN Inlet and outlet ports."
Billet pump controller (P/N 16302) recommended to keep fuel cool on long trips.

Originally posted by DynoDon
Here's the pump from Aeromotive....


A1000 Fuel Pump, P/N 11101

For fuel injected engines:
up to 1100 HP - naturally aspirated
up to 800 HP - forced air induction

For carbureted engines:
up to 1300 HP - naturally aspirated
up to 1100 HP - forced air induction

Flows 600 lbs. per hour @ 13.5 Volts and 45 PSI.
"Features -10 AN Inlet and outlet ports."
Billet pump controller (P/N 16302) recommended to keep fuel cool on long trips.

a little over-kill there for a carb. dyno!!!!! might not run a MPFI. JMO

Hey Mike, just thought I would throw in another option.

Originally posted by DynoDon
Hey Mike, just thought I would throw in another option.

for carb. and TB you have enpugh fuel, thats for sure, but those MP needs a lot of pressure.