Are you sure the new cooler would fit the existing space front to back? Mine was sized for an old landfill 100qt cooler and when I wanted a better one I had to downsize the cooler to get it to fit in the frame. it wasn't the tube to tube length of the cooler that limited me, but the front to back width. I have often wondered how they make the cooler bay for big coolers and have suspected they leave those diagonal bars off.
Good luck and post some pics when you're done.
Good luck and post some pics when you're done.