55.2-59 Seats that fit where the gas tank was.

[bigshrek64]

Hello all,
Im building a 56 truck taskforce truck, im relocating the fuel tank to the bed, well im 6'4" 280lbs, with bum knees, im trying to find all the legroom i can, and im wondering if anyone makes a bench seat that fits where the fuel tank was, or if anyone made their own, if so what did you start with and how much did it cost to get redone after cutting it down, and if you could post pictures. I cant seem to find any on google. I know if i cut down a seat and shave some foam i can pick up 6" add some shortie pedals and hopefully add 8" total of legroom.