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Old 06-25-2018, 12:06 PM   #1
epfatboy
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Join Date: Mar 2018
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LSx Conversion, fuel sending unit

Quick question:

Replaced my '74 tank with an '87 tank and sending unit. I have the Feed and return lines worked out but what is the 1/4" fitting for on the sending unit?

I'm guessing it is a vent just not sure what to do with it?

Also the near the filler on the tank and on the filler neck there is a provision for a 5/8" hose. Is that for fuel overflow? Is that also like a vent since I assume the cap is not air tight?
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Old 06-25-2018, 12:18 PM   #2
MalibuSSwagon
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Re: LSx Conversion, fuel sending unit

The 1/4 line is for an evap. I hooked this up to the original evap line going to the engine bay but never did anything beyond that. I don't have any fuel smell issues.

Those two 5/8 fittings on the tank and the filler neck should be connected together, it's the pressure relief for when you fill the tank. Should be a factory molded hose available to connect them.
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Old 06-25-2018, 01:31 PM   #3
mongocanfly
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Re: LSx Conversion, fuel sending unit

The 1/4" on mine had a tank vent on it....nothing wrong with evap if you want....
The 5/8, Malibu covered as a tank pressure fill relief ,hooked to fill tube
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Old 06-25-2018, 04:45 PM   #4
epfatboy
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Re: LSx Conversion, fuel sending unit

So can I just vent it to atmosphere? Should I put a one way breather on it as well?
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