73-80 gas tank... 81-87 filler neck?

[BADAZ chevy guy]

So here's the problem The OEM gas tank in my 77 C10 has a 1-3/8" filler tube on the tank. The bed is off a 81-87 C10 with gas doors and the filler tubes are 1-3/4". Has anyone found a solution for this problem? I took a piece of radiator hose with a 1-3/8 ID and fit it between the filler hose and the tank filler tube.

[Your41Plague12]

Tried the same thing (using a 73-80 tank in my 83) and there was really no good way to do it. I sucked it up and bought the 81-86 tank for about $100. Worth the money to do it right.

[rich weyand]

That radiator hose is not certified for gasoline. It will crack and craze and fail, dumping gas all over.

My 1978 when I bought it had the same issue. It was the original 1978 tank, with an 86 box with both fuel doors. I replaced the 30+ year old tank with the correct tank with the larger fuel inlet and used all the correct hoses. Put both sides in while I was at it, with a motorized Pollack selector valve, then put a second fuel gauge in the empty dash position so I can read both tanks all the time.

That original tank is full of garp and ready to rust out anyway. Put in the correct one new and use the correct hoses.

[gramps77]

Originally Posted by BADAZ chevy guy

So here's the problem The OEM gas tank in my 77 C10 has a 1-3/8" filler tube on the tank. The bed is off a 81-87 C10 with gas doors and the filler tubes are 1-3/4". Has anyone found a solution for this problem? I took a piece of radiator hose with a 1-3/8 ID and fit it between the filler hose and the tank filler tube.

I literally just ran into this yesterday. There has to be a way to make an adaptor to go from new to old. Any weld shop should be able to do it. Im going to check it out soon

[BADAZ chevy guy]

Originally Posted by rich weyand

That radiator hose is not certified for gasoline. It will crack and craze and fail, dumping gas all over.

My 1978 when I bought it had the same issue. It was the original 1978 tank, with an 86 box with both fuel doors. I replaced the 30+ year old tank with the correct tank with the larger fuel inlet and used all the correct hoses. Put both sides in while I was at it, with a motorized Pollack selector valve, then put a second fuel gauge in the empty dash position so I can read both tanks all the time.

That original tank is full of garp and ready to rust out anyway. Put in the correct one new and use the correct hoses.

I know the rad hose isn't going to last long. I only put it in there as a temp stop gap so I could get some gas in the tnk

[cool68]

Originally Posted by gramps77

I literally just ran into this yesterday. There has to be a way to make an adaptor to go from new to old. Any weld shop should be able to do it. Im going to check it out soon

.
when you talk to guy at fab welding shop ask if the later neck could be welded to the earlier tank. as most know, trucks like my '76 (in California) can be very hard to put gas in because of small neck. Thanks

[rich weyand]

A muffler shop should be able to braze two short pieces of a couple different diameters of exhaust pipe together for you as an adapter. Probably cost you 10-20 bucks.

Then use cut-offs of the correct filler hoses, or at least fuel-certified hoses of the right diameter and some band clamps.

[hrc200x]

I'm thinking along the same lines as rich, even a auto parts store may have an exhaust reducer pipe premade, only thing it won't have is the rolled edge that gives the rubber hose and clamp somthing to bite to help reduce a leek. Not sure what sizes are available but its worth a shot.

When I ran across this issue I bought the correct tanks.

[BADAZ chevy guy]

I was able to talk to the PO this evening. I got a new set of tanks when I bought the truck, but they were also for a 1977. The PO is going to see if he can find the invoice for the 77 tanks. Maybe I can trade then in for later model tanks sense they're still in the original boxs..

[1774btcrew]

I ran into this on my 77. I used 1980 filler necks with no problems. They must have stuck with the same tanks in the pre 1980 trucks that had gas doors.