big gas tank

[clemdaddy]

looking for a bigger than stock gas tank that still fits behind the seat. I have one in my 65 dually but it came from a parts pile so I can't ID it. might be from a 67-72, not sure. all I know is it's the same as stock tanks except about 8-10 inches longer. I think it holds around 4 more gallons.

I want to order a new repro so the range of years is what I need.

thanks...