gas line question

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Feb 8, 2016 | 11:11 AM

#21

Dins74

Instructor

Joined: Apr 2009

Posts: 126

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From: LA CA

Hey madam what would you think of T 'ing off on the fuel inlet side befor the pump. Are these mech pumps strong enough to keep the carb full and recirculate fuel for a makeshift return

din

Feb 8, 2016 | 11:50 AM

#22

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

If you just T it back to the tank, the pressure in the line going to the carb will drop to almost nothing. You need an orifice in the line to keep pressure up. The .040" orifice mentioned is pretty small for an 8 gpm pump; also, that won't allow much flow in the return line.

But, it works...so that is one way to do it. My guess would be that anything under 1/8 inch would work fine. That should keep enough pressure in the carb line so that it would always stay 'charged'.

Feb 8, 2016 | 12:30 PM

#23

ddawson

Le Mans Master

Joined: Mar 2001

Posts: 5,738

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From: Lincoln, CA

When I went from a QJet to a Holley I kept the OEM fuel filter with the built in return.

Feb 8, 2016 | 12:48 PM

#24

colesweat

Instructor

Joined: Dec 2012

Posts: 118

Likes: 2

From: rancho cucamonga ca

do they make different size lines for different motors? a 2 barrel 327 can not have the same line as a 427 l88! what do you think

Feb 8, 2016 | 01:20 PM

#25

Alan 71

Team Owner

Joined: Sep 2006

Posts: 31,273

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From: Westminster Maryland

Hi,
I believe the tank to pump supply line for all 327,350,427,454 engines from 68-72 was 3/8" while the return line, (for applications that had a return line), was 1/4".
Regards,
Alan

Feb 8, 2016 | 01:34 PM

#26

colesweat

Instructor

Joined: Dec 2012

Posts: 118

Likes: 2

From: rancho cucamonga ca

why would it need a return line on a carb motor?

Feb 8, 2016 | 02:25 PM

#27

ddawson

Le Mans Master

Joined: Mar 2001

Posts: 5,738

Likes: 644

From: Lincoln, CA

Vapor lock.

Feb 8, 2016 | 03:53 PM

#28

madam

Instructor

Joined: Feb 2013

Posts: 193

Likes: 2

From: Illinois

Quote:

Originally Posted by Dins74

Hey madam what would you think of T 'ing off on the fuel inlet side befor the pump. Are these mech pumps strong enough to keep the carb full and recirculate fuel for a makeshift return

din

The supply line comes off the bottom of the tank and the fuel pump is lower than that therfore a gravity feed to pump is present. The return line to tank is near the top of the tank. Since the tee would be ahead of the pump fuel will never get there (up hill) ans serves no purpose. Plus you would have a closed system from pump to carb and could vaporlock.

Just my thoughts.