[fauXGT]

While my situation is a bit different that yours being I have C4 suspension on a stock frame, I opted to remove the spare tire crossmember to fit a tank there. Early 50's Chevy sedan tank for a side fill. I then made the re-enforced back piece so it didn't turn into a Pinto timebomb, but the frame was also a bit tweaked when removing the old cross piece. Used a hydralic spreader and then built the extra support. Just measure before cutting out the old to get the proper dimensions back. Like I saw in my circumstance.... cutting out the old can show some un-sprung issues.