Aftermarket mechanical fuel pump questions
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Senior Member
Joined: Jun 2001
Posts: 673
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From: Northern California
Car: 1992 Camaro Z28 & 2k3 Cadillac CTS
Engine: LB9
Transmission: T56
Axle/Gears: 3:43
Aftermarket mechanical fuel pump questions
Im looking for an aftermarket fuel pump for my Lg4 and i havent seen any direct replacements, but i have a holley fuel pump itching to be installed. My question is that if i go to install this holley fuel pump, (#12-834) it lacks a return line and also i will have to find the correct plumbing for it. Any suggestions? I heard about a walbro fuel pump, is that for fi cars? Does anyone know what the stock intank fuel pump flows for an Lg4? Should i go to replace that one as well?
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Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
AFAIK there is no in-tank fuel pump on LG4 cars.
The stock one is fine up to at least 400 crank horsepower (speaking strictly from experience). You can help it work a whole lot better at high RPMs with a lightweight rod, such as from Moroso.
The stock one is fine up to at least 400 crank horsepower (speaking strictly from experience). You can help it work a whole lot better at high RPMs with a lightweight rod, such as from Moroso.
Thread Starter
Senior Member
Joined: Jun 2001
Posts: 673
Likes: 0
From: Northern California
Car: 1992 Camaro Z28 & 2k3 Cadillac CTS
Engine: LB9
Transmission: T56
Axle/Gears: 3:43
im pretty sure there is an intank pump on my car, almost positive. im almost sure 87 was the only year they did it. you can hear it whine when i turn the key to the on position.
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Joined: May 2001
Posts: 698
Likes: 1
From: Houston TX
Car: 84 Z-28 Camaro, 2022 2500 silverado
Engine: 383
Transmission: T-56
Axle/Gears: richmond 3.73, eaton posi
Half year '86's and '87's had a in tank fuel pump not sure what the flow or pressure on it was though
Senior Member
Joined: Sep 2001
Posts: 564
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From: Cathlamet, Washington
Car: 87 Formula
Engine: 327
Transmission: 700r4
Axle/Gears: 3.23
My 87 formula with LG4 has an intank pump as well as the mechanical. The in tank is very low pressure. But i don't know exact specs. Having both pumps would make me very leery of putting a mechanical pump without return on. The carb needle is going to have to try to stop both pumps. Not knowing what the stall pressure is on the electric pump means you'll probably have a sever flooding problem without the return.
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