andrewcrocos1

Interested to hear peoples opinons and experices with fuel lines sizes and fuel pumps.
I have a mildly worked 351c. 650 holley, edlebrook performer, 234, 244 and 580 lift cam which is good to 6000rpm, bigger valves and alot of porting. The motor is in a xc sedan which was orginally a 6cyl. The current fuel line is 5/16. I know I have to upgrade the fuel line to 3/8. Do I have to change the fuel pickup tube (in the tank) to a larger dia? (3/8).
Will a new stock fuel pump be able to cater with this set up, or will I needed to run a larger mechanical one or an electric one. I've been eyeing off a holley blue.
If I run a holley blue, can I run a 3/8th line to it, or do I have to run a 1/2inch line. Also what fuel pressure do I run with the in line fuel regulator.
Any help and experience will be muchly appreciated.

xacoupe

I have 5/16 line to my XA with a holley blue (didn't really want an electric pump but there was no fuel pump concentric in the motor, which I didnt find out until it in)
I have no real problem with fuel delivery. I run about 4-4.5 psi

paull

Up to 302, all had 5/16 fuel lines. 351s had the 3/8 as standard. As far as I know all pickups are the same size but will stand corrected. If you have the 351 do not dick around with a smaller line, better yet, being a modified engine go the 1/2 inch line, better to have it and not need it rather than need it and not have it.

As XA-Coupe says, nothing wrong with holley fuel pumps.

TTNOS8

I run 3/8" from the tank to a holley blue, with a similar engine to yours, also with a nitrous system running off the same supply line and have had no fuel supply problems with the reg set to just under 8psi.

I was considering running 1/2" and after asking some blokes more in the know, they asked me "WHY?"

i was running a aftermarket mechanical which was fine, and then a stock replacment goss fuel pump, and it just used to run out of puff after nailing it through all the gears.

at least go better mechanical pump, and probably 3/8", but you'll love having a holley blue (except for the noise)

andrewcrocos1

Thanks fellas.
TTNOS8, do you have to a 1/2 inch supply to the holley blue and then 3/8 from there on, or do I just run 3/8 all the way.

TTNOS8

i run 3/8" all the way.

Dellboy999

We had a holley blue running on my brothers HQ Statesman, and they are pretty noisy buggers, you can mount a big bit of rubber to stop the vibration noise some what, but it doesnt do alot. He ran 3/8 all the way and ran 14s, not bad for a mild worked motor in a 2 tonne car, shame the brakes were stock, it didnt stop real good.

Dellboy999

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WBT56

If you are running an electric pump in/near the tank, line size doesn't really matter. If you are running a pump up the front of the car, you need to keep the line as small as possible without restricting flow, normally 3/8 is fine. What happens is when the line is too big, the fuel travels too slowly and picks up too much heat. This, coupled with the fact that the line is under partial vacuum from the pump can cause vapour to form in the line, killing fuel supply, in high fuel demand situations.

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brenx

I run 1/2" from the fuel cell the to regulator and then 2 3/8th lines into each fuel bowl. When I am pushing it the fuel pressure drops off to 4.5psi but I haven't got the pump anywhere near it's max. I run a Mallory 140. Much quiter than a Holley blue. Holley blues are noisey as hell!.

For your engine I'd suggest buying one of the new mechanical pumps for Clevelends. Try www.superplus.com.au

A stock Goss mech pump will flow enough fuel for 5800rpm. Aftermarket mechanical should do 6000-6500rpm provided you go no bigger than 650dp carb size.

XBWGN's wagon had a similar cam in his 351 (that failed). Just ran stock line and a mech pump. Max power was @ 5400rpm. Don't believe box specs. My cams (Crane F246 copy) supposed to be making power to 7000rpm. It drops power @ 6300rpm pipes on and 6800rpm pipes off. Your head porting will effect the cam power range.

[edit] I used to run a 3/8th line with a Holley blue. Didn't have enough volume or pressure to prevent my engine leaning out. I had major issues. I sent the car off to a dyno tuner (Hallam Perf) and said "fix this". I love it when I have the $ just to tell someone to fix it. Instead of me buggerising around.

Brenden

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