I think this is the right forum I made some gas tanks yes that is tanks as in 2, for my 38 GMC. They are going under the cab/bed between the frame. They are simple boxes 36"x12"x9" 16 gauge cold rolled steel with 2 baffles I welded them with a wire feed welder did an ok job but I do have a few pin holes plus it was suggested to me to use a gas tank sealer even if I didn't have any holes, so here is the question where do I get a good gas tank sealer would a parts house carry any.

One more question are the GMC gas gauge sending units the same as the Chevy ones in size I am assuming they are because Almost everything else is interchangable

1938 Gmc 1/2 ton