Well I went into town today to buy some parts. Got talking to the mechanic at the GM dealership. He said he put the larger tanks on his own 81 long box years ago. Said he cant remember all the details except it was a pain.
#1 He said that unless you have the box off the truck itas a real pain. Example unhooking up the wires to the sending unit.
#2 He said with the longer tanks the frame brackets are in the wrong spot. He couldnt remember if he had to just move the back brackets or get replacement ones for a 20 gallon tank.
On the plus side he said the frames are all drilled for the new bracket location.
Anyway im thinking the heck with it. Im going to put a flat deck on my truck anyways.
Right now I have a huge third tank in my bed but its not DOT approved and it doesnt have a fuel gauge. I noticed in the parts store that they have bed tanks<probable 60 gallon> that are diamond alunimun and DOT approved for gas. These tanks mount right in the bed of your truck. Im thinking when put the deckl on my truck I will buy one of these bed tanks and then take off my factory tanks.
With the factory tanks gone I can build custom running boards that I can bolt directly to the frame <think strong>and those old fuel tanks wont be in the way.