'72 Gas Filler Neck

[Dashman]

I'm at the end stages of the rebuild on my Dad's '72 K10. I was merely a boy growing up with this truck, so I don't know all of it's service details. I say these things as a prelude to my question/s.

As recall, the tank could only take 16 gallons. Yes, I've seen the specifications manual that shows 20 gallons for K10s and 21 gallons for K20 (page 3). It makes me wonder if my Dad ever had to replace the original tank, or if St. Louis ran short of the specified tanks?

I know for certain that my Dad lost the key for the locking cap, and the "mechanic's shop" had to forcibly remove it. Thereby damaging the filler neck. The locking cap on it currently does not fit well, and the gasket deteriorated long ago, so the gas would slosh out when full and in a right turn.

The damage to the filler neck isn't going to allow the proper locking cap to seal correctly. I have been unable to locate a 2" filler neck bung. Now that the truck's gas tank has been bone dry for a number of years, I could cut this neck, repair the damage, and then weld it back. ...or I could replace the tank with a Spectra GM49B (see I read here a lot, thank you BTW).

[Sheepdip]

I'd replace the tank, it'll fit and be clean.

[PbFut]

If within your budget, replace and be done with it.
If you remove and weld, best to clean, etch and seal inside with a good tank sealer kit.
Be sure to add up everything needed to fix. It may be the same as replacing.

[howzzzit]

Buy new

[54blackhornet]

Don’t waste time on old gas tanks if a quality replacement is available…

[Dashman]

I didn't mention that I inspected the tank with a flashlight, and when I flushed it with gas it was only moderately dirty. The inside looked rust free. I did recall witnessing a gas leak when the truck was parked about 20 years ago, and I did find the cracked hose underneath. I replaced those hoses, and the evaporative canister.

FYI, the new 20 gallon tanks are 57" long. Mine is 50" long. So yeah, 16 gallons.

I am trying to take care of all the old issues while putting it all back together again, so I thought I'd address this filer neck and the gas sloshing out. I think the only reason I was trying to hold onto it was to reduce costs and the hassle of removing it. I can use this tank to get the truck driving again, and then purchase a new tank.

A 2" filler neck bung would have been nice to find, but a new tank is the proper solution and 4 extra gallons sounds better for the future. Thank you for the advice!