[mr48chev]

Moving or replacing the rear cross member Is pretty well standard procedure when you do the tank swaps.

You would think that someone would be selling a bolt in/weld in replacement crossmember specifically but I don't remember seeing one.

Several of the guys have made them for their trucks and hopefully a few post detailed photos.

It isn't rocket science, you get a length of square tubing with the right dimensions and weld it or figure out how to bolt it in place moving it back far enough to clear the tank while not blocking access to the holes in the frame that the rear bumper brackets bolt to.

When I did mine way back when I used a piece of what look and may have been the track for an overhead door that rolled sideways with trolleys inside the track that I dug out of the scrap pile at work. It was free and the right size. I used a 20 gallon aluminum tank intended to be used as an auxiliary tank on my moms conversion van but works great on the 48. The capacity is nice on long road trips but 16 gallons is plenty unless you have an engine that drinks gas like a Key West bar fly goes though beer.