Can I use the fuel sender " fuel outlet" connection for fuel return?

I use a low pressure (6 psi) Holley Red electric fuel pump for my truck's NO2 system. I just switched my fuel pressure regulator to a "bypass style" due to pressure creep. Now I need a way to return this bypassed fuel back to the tank.

My tank setup has a fuel feed line coming off the bottom for the supply, so I am not using the stock fuel line connection that comes off the top of the fuel level sender unit. Is there any reason I can't use that connection for the fuel return line?

If not, I also bought a JEGS -6AN compression fitting designed for this purpose but it requires that I drill a 1/2" hole in the top of tank. If I don't need to drill a hole in the tank that would be preferable.

What do you think?

I think there may be a check valve in that connection/nipple (internal to sender unit) that is designed to prevent the fuel from draining out of the fuel line when the engine is shut off and the front of truck is higher than the tank. That would make sense.
So, if I try to use that connection for fuel "return" the fuel won't make it into the tank. Maybe I can test this theory by connecting some hose and blowing into the tank via the nipple.

did your truck come with the " hot fuel" system?  i know some years with the 460 did but im not sure of which. the ones which had it had a return line to keep the fuel circulating and prevent vapor lock. not unlike what you are wanting to do now. if not then you may be able to use the existing pickup tube as long as it has no obstructions. personally, i would modify the sending unit before drilling a hole in the tank. just my opinion.

Thanks for your reply. Sorry for not seeing this sooner - I almost forgot I posted here.

My '82 F250 came with a 351W (EEC-III), and I swapped in the 460 about 20 years ago, so no hot fuel return. I could pull the sender and drill a hole in it for return line. But I was thinking it would be easier to drill a hole in the top of tank and then I wouldn't need to doing anything extra if I was to ever replace that sender.

I already had the tank out once (then I had two -8 AN fittings welded to bottom rear corner of tank and one -6 AN fitting added to the top for the return. That was for the MSD Atomic fuel injection setup (which runs at 50 psi). I should have added a second return line then, but was using a dead-head pressure regulator for the low-pressure pump (6 psi) for my nitrous setup.

PS. If I drill a 1/2" hole in the top of the tank without removing/draining the tank - what are my chances of not blowing myself up? Perhaps I could setup a fine mist of water spray over the tank to reduce chances of a spark...

CountryBumkin wrote

PS. If I drill a 1/2" hole in the top of the tank without removing/draining the tank - what are my chances of not blowing myself up? Perhaps I could setup a fine mist of water spray over the tank to reduce chances of a spark...

I would think if you drain the gas and fill the tank all the way up with water, you would be safe. You just have to make sure that the water comes all the way up to where the drilling is occurring. Maybe roll the tank on its side a bit so you are sure that area is underwater.