1953Panel(Leo) isn't your panel a 1/2 ton?? if it is then I believe the tank picture Bilyray has in not like our half tons. It looks to long. Also, if your is a half ton then the tank straps attach to the frame AND to the underside/through the plywood floor. Mine is just like yours IF its a half ton.
If its not a half ton then disregard everything I said
Just for info.... the filler neck on my half ton has a little curve in it and the rubber connector hose is about 3 inches like you suggested. I have my old original laying around somewhere.... So, is your a half ton Leo?
