Building Your Own Gas Tank

One of the biggest problems with these old trucks was the location of the gas tank. Some how putting 16 gallons of gas in the cab behind the drivers seat doesn't strike me as being the best of choices. The solution of course is to mount a tank between the chassis rails under the bed. There are several commercial tanks available but most of them have the filler built into the top so the tank is filled through a hole in the bed floor. I'm planning on polished stainless steel or aluminum diamond plate for the bed floor and I would rather not have the gas filler located there. I looked everywhere but just couldn't seem to find a side fill tank that would fit the space and still hold 20 gallons. The solution was to make my own.

Great care must be taken when making a gas tank for a couple of reasons. First, you never want it to leak and second, it must be supported adequately. I happened to have a bunch of 14 gauge cold rolled steel lying around (left over from replacing the floor of the cab) so thats what I used. Its much heavier than you would normally see used for a tank but weight wasn't an issue and I wanted a material that would be easy to weld.

Here you see the finished tank in place. It will hold just a touch over 20 gallons and is equipped with a GM compatable sending unit, filler with vent and and a small sump for the outlet.

This shot shows the filler tube. The filler and vent were removed from the stock tank and welded in place here. The stock cap and filler tube will mount on the rear of the drivers rear fender. All the seams in the tank were welded both inside and out except the top. Then compressed air was used to look for leaks. A couple were found and rewelded and the tank was sealed with a good quality gas tank sealer. The sending unit is a universal GM sender purchased through JC Whitney and appears to be a quality peice.

This shot shows the small sump where the outlet is located. Inside the tank is one baffle designed to limit the sloshing of fuel when turning corners. Don't build a tank without at least one baffle. You can also see the 1 1/2" x 1/8" strapping I used to support the tank. I welded the strapping to the tank so the unit comes out in one piece.