# fuel lines



## Topkat (Sep 9, 2010)

I have two rubber fuel lines (Metal behind that) that stick out about 5''s from the right side of the cross member.
I'm assuming one is the vapor return line?
How do I tell which is which short of slithering under the car and following them back ?
thanks as always!!!


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## Instg8ter (Sep 28, 2010)

if they are old i would replace them, they can bleed air into your system if they are old and cracked even though they may not be leaking. If your car has been sitting for a long time i would grab a few extra gas filters while you are at the parts store also, as they will get plugged once the system cycles through a tank of gas or two.:cheers


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## GTO JUDGE (May 14, 2005)

On my '70. The feed line runs the driverside. There is a rubber fuel line at front xmember that accepts the metal line that runs behind the xmember to the passenger side that attaches to the rubber hose on passenger side. 
That metal line is the return line and is smaller in dia to the feedline. The return line runs along passenger side. Smaller dia line= return line.


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## dimitri (Feb 13, 2009)

I run a small inline fuel filter before my fuel pump. I put it between the frame and pump. It is a lot easier changing this filter than the one on the carb. I still have the one on the carb, but it never gets dirty.


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## geeteeohguy (Feb 2, 2008)

On a '67 GTO, both the fuel line and the vapor return line (if equipped) run along and thru the drivers side of the frame. 6 cylinder Tempests had the fuel lines on the right side of the frame, as Topkat describes. Topkat, is your car a Tempest? In California, I have the original steel lines on both my '65 and '67, but being CA, they are not rusty and are in good condition. Only the rubber ends need attention every few years. Heavy duty cooling system cars (trailer package and AC equipped) in '66 and '67 had vapor return to help keep the gas cool and prevent vapor lock. Cars with the standard non HD cooling system just had the one line in those 2 years....


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## Instg8ter (Sep 28, 2010)

:agree Dimitri i ran a clear plastic before pump to hopefully add longevity to the good filter at the carb


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## Topkat (Sep 9, 2010)

My bad , they are on the drivers side.
and yes its a GTO


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## BearGFR (Aug 25, 2008)

Topkat said:


> My bad , they are on the drivers side.
> and yes its a GTO


Usually the smaller diameter line is the return line, the larger is the feed line to the pump. The factory sizes for 64 (and others) were 3/8" on the feed, 1/4" on the return.

Bear


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## geeteeohguy (Feb 2, 2008)

Bear has it correct. The 1/4 " line is the return line. The '66-'67 GTO's with the return line had two different set ups: some cars used a 3-fitting fuel pump, and the small fitting connects to the return line. Others, like my own '67, use a 3-fitting filter that mounts up by the T stat behind the alternator. It's been so long, but I don't think I even have a filter in my carb....it's the original QJet and I repaired the threads on the filter housing in 1984 or so....been running an in line off the pump ever since. Much bigger and better filter, too.


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## pontiac (Mar 6, 2011)

filter in front of pump will require higher suction pressure as fuel gets clogged and plastic filters are not rated for vacuum service, only for pressure. best on pump outlet.


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## GTO JUDGE (May 14, 2005)

My Q-jet is using the internal ceramic filter. I do not like the look of the inline ones.


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## BearGFR (Aug 25, 2008)

GTO JUDGE said:


> My Q-jet is using the internal ceramic filter. I do not like the look of the inline ones.


That's why I hid mine inside the frame rail behind the tank, 









..but then I put a rear sump on my tank also..










All the welds started of looking reasonably ok...









...but then when I tested the tank it leaked, so I went over all of them again and went a little overboard, but it doesn't leak now. 

Bear


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