I'm considering options for doing something similar. I've got an old short box with the 12 gallon tank and I'm looking to add a second 18 gallon tank lengthwise at the back of the truck. I've spent copious amonts of time under the truck measuring and planning, heres my two bits on options:overeasy said:I'm going to change my gas tank with a 18g one. I'm going to mount it between the frame rails. My ? is how close to the exhaust would you consider safe? I want it low as possible.
I did the 2nd stock tank on opposite side in an 82 ran dual exhaust between the tanks(very close tolerances) I got some stick on heat shield from summit racing to put on the tank and never had a problem. I now have an 85 runner and am going to do the same thing.As far as the filler neck goes you can either install a y in your existing filler neck and fill both tanks from the stock location a muffler shop can fab one up cheap. Or i turned the tank 180 deg and installed another neck thriough the passsenger side using a filler neck from a mid 70's ford truckdkc1657 said:Thats not an option for me, I still run the factory box with only a 3" body lift. Are you doing that with the factory box?? Those 18g tanks are pretty deep tanks. You know I'm amazed at the lack of room in these old trucks. I've got an 81 short box, and trying to find room for an auxiliary tank and a second battery is not easy.