OK so I've decided to cut the spare tire well out. I'm thinking to use a Ford gas tank (Yea I know) like the ones below. The Fairlane tank seems promising as it is 30 1/2" wide flange to flange. The stock spare tire well area after removing the well, should allow for this to drop in with very little addition modifications other than cutting the proper size hole. then the gas tank and spare well are taking care of at the same time and no bulky fuel cell in the trunk. The top of the Ford tank would be the finished trunk floor. Then either weld on a filler cap flange and fill from the trunk or reroute the filler tube inside the trunk.
FORD FAIRLANE & TORINO
1966-69 Fairlane, 1968-69 Torino includes 2 door & 4 door sedan, hardtop. (except station wagons). 20 gallon, (30-1/2"X37-3/4"X8-1/2") without drain plug, high quality Ni-terne plated steel gas tank. Includes lock ring & gasket for sending
MUSTANG & COUGER
FITS:
Mustang: 1964,1965,1966,1967,1968
Cougar: 1964,1965,1966,1967,1968
Made by SPI and of High quality Ni-terne plated steel gas tank with 3-year warranty and comes with drain plug, also Includes rubber O-ring & lock ring for sending unit.
Size: 16 gallons. Dimensions: 32-5/8" x 24-1/2" x 8"
Replaces Ford Original Part Number: C5ZZ9002D