Hey guys, a buddy of mine is wanting to convert his truck (78 Chevy 1/2 ton) to fuel injection from a carb.

One of the things holding him back is having to set up his gas tank with a return line. He doesnt want to have to buy one and he's having trouble finding any tanks that would fit that already have a return line.

One idea that i've ben thinking about lately is adding a return line into the filler neck. I know that we could definitely make it, I'm just curious to if there would be any problems with it.

The idea I was thinking about is to take a piece of pipe with the same diameter as the filler neck tube, maybe like 3 or 4 inches long. Then attach a piece of smaller pipe (1/2") at a 45 degree angle from the gas cap side of the filler neck. That piece of pipe would act as the return into the tank and then just run the rest of the line as any normal F.I. system would be set up.

I've seen repair kits for filler necks that have a sort of rubber/ plastic-ish material that is meant to cover cracks or splits in the filler tube and then hose-clamped in place. If one of these pieces was used on each end of the pipe I mentioned to make the pipe a continuous (and hopefully leak free) part of the filler neck, so when filling the truck with gas the filler tube would work the same, and fuel coming down the retun line from the motor would go through the smaller piece of pipe and because it is attached at an angle the fuel would go towards the tank and away from the gas cap to avoid any problems there.

I know I may not have explained this in the best way, but if you guys understand what I mean, could it work? It would be pretty simple to make, very inexpensive, and the factory gas tank wouldnt have to be replaced, all the welding could be done away from the truck.

What are your thoughts on this?

This could work:
http://www.jegs.com/i/Moroso/710/65385/10002/-1?parentProductId=743759
All you have to do it cut the tube, no welding needed.

Your idea would work as well, easier than modding the tank.

Use the vapor return port on the tank

I believe my 78 had the vapor return and a fuel return
My 79 does have both of these.

Do you really need the vapor return if equipped????

Might also try just getting the sending units from any 80-87 pickup as they all use the same tanks within the wheelbases. (73-87)

The later tank sending units will be equipped with all the ports needed.

This could work:
http://www.jegs.com/i/Moroso/710/65385/10002/-1?parentProductId=743759
All you have to do it cut the tube, no welding needed.

Your idea would work as well, easier than modding the tank.

Oh right on, that is basically the idea I was thinking of, the only difference is that I was thinking of adding the actual return line pipe on an angle, I'll let my buddy know about that kit, would probably end up being about the same price as buying the metal and the 2 repair kits that I mentioned, same exact idea though.

Thanks

Use the vapor return port on the tank

I believe my 78 had the vapor return and a fuel return
My 79 does have both of these.

Do you really need the vapor return if equipped????

Might also try just getting the sending units from any 80-87 pickup as they all use the same tanks within the wheelbases. (73-87)

The later tank sending units will be equipped with all the ports needed.

Thanks I'll tell my friend that too, i never even thought about that since I was thinking more about tanks like mine, thanks a lot guys. :beers:

I was looking at the Moroso kit myself, but how do you cut the neck off the tank - hacksaw? Just dont want an explosion if you know what I mean.

This is what I did with a simple bung kit for 11.99, comes with 2 teflon/nylon washers. If he has room on the top of the tank, that would be the place to put it, so the return line doesnt have to "push" the gas in tank to get out.

http://i134.photobucket.com/albums/q116/VGIORDANO_2007/IMG_1611.jpg?t=1259588955

I did it even simpler. I had a threaded bung welded to the filler neck (tank was new) when the sump was added. I routed the return to it. from the fuel pump mock up:

http://i168.photobucket.com/albums/u165/Bowtie-Bry/TECH/DSC03275.jpg

I copied Bowtie-72's on my Pontiac A-body. Works good on mine.

I ran mine to the vent tube.

the boat comp. i work for just loops from the regulator back to the fuel line behind the pump works fine for the years i have been there

Thanks guys, were going to get the truck into the shop and check out what there is to work with, vent tube will be the first idea, and if not he likes the idea of the filler neck idea, thanks guys :thumbsup: