decided to box in my frame for a cleaner look, already had it partially boxed in at the front due to the suspension swap, the rear end was c-notched and partially plated with 1/4 inch steel, i ran 1 1/4 inch conduit tubing inside the frame only welding it at 3 places in case of chassis flex, then i started to plate the sides up,bent up pockets so i can get to my bed mounting bolts, for the rear, i`m using a 69 mustang tank so i made my bracket up and welded nuts inside the frame to attach the tank frame,needed more side room for the tank so i cut the bottom of the rails enough to clear the tank,didn`t have anything fancy to bend the steel in the back frame so i welded the top plate to the frame, heated it up and bent it into a oval shape and then welded the bottom to the frame.