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Old 07-21-2013, 09:27 PM
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shineybike shineybike is offline
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Default Need Vapor Return Line Help

I have a '68 Lemans, 350, TH400, non AC car. I have been having a hot start issue after running a while and then letting it sit. I'm moving from Maine to Delaware and suspect my problem may get worse. Car has the stock fuel pump with no vapor return. From what I've read on here it may be due to the fuel heating up once it's shut off.

Can anyone tell me what i would need to convert it to have a vapor return line? What fuel pump? Any other parts besides the return line? Does it connect to the passenger side front corner of the tank where the other vent is? If I remember right when I put the tank in there was an extra fitting there besides the one for the stock tank vent. Thsnks

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Old 07-22-2013, 02:06 PM
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69goatboy 69goatboy is offline
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You obviously would need a FP with a return line, one for a 69 GTO will work.

Then the line itself, should be 1/4", IIRC. The factory snaked the line (with the fuel line) through the driver's side frame near the upper control arm shaft area. If you choose to do this, remember some sort of protective cover for the line to keep the line from chafing on the frame. (I used battery cable loom on mine).

Then you'll need a sender unit with a return line port (I know my 69 has it), for that is where the return line will be plumbed to. Not to the pass side front port of the tank itself. That's a tank vent.

I think that should be it. Please, somebody correct me if I was wrong anywhere.

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Old 07-22-2013, 02:48 PM
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2 bbl or 4 bbl? Sounds crazy but the 2 bbls have a hot start problem related to the carb. There was a technical bulletin for this back in the day. The fix was a notched gasket.

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Old 07-22-2013, 05:21 PM
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Thanks for the replies. I hadn't thought about the return line connecting to the sending unit. Good info. My car was originally a 2 bbl., but has a 4 bbl on it now.

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Old 07-23-2013, 06:08 PM
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My 68 GTO w/AC has the return line from the factory. Must be the AC cars that got it.

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