I just bought a '71 Stepside

[Dova]

Well, i just bought a '71 stepside it was restored a few years ago but the owner didn't swap the gas tank out. does anyone know how much it will cost to relocate the tank to the rear? i want it under the bed with the filler under a flip up license plate. i seeen a guy in a build thread do it just wondering how much it will cost to do. i also seen where a guy on here sells them but don't remember where i seen it or who sold it. i want a 20 plus gallon tank. i want the tank removed because i want to go with larger tahoe seats that are power leather and heated. so i was just wondering about how much this would cost and how long would it take? i plan on doing it in hopefully a day when i come home on leave. i will post pictures when i get off work and can get on my pc. would it be better to bolt a frame for it or weld the frame for the fuel cell up? any info on this would be greatly appreciated and i will post pictures of the whole truck in a couple of hours