hey guys so im doing a frame swap on my 55.2 chevy pu it is sitting on a 84 chevy c10 frame i have about a 27" square in between the rear frame rails in the back under the bed. i want to try to make the filler neck come out of the back with a fold down license plate. has anyone done a gas tank relocation? and does anyone have any suggestions? also if i go with a fuel cell what are the pro and cons to plastic vs. aluminum vs. polyurethane ? is there any oem gas tanks that would be close enough to fit in the back? let me know what you guys think really appreciate it thanks guys big help kujo