I think you want a little clearance to keep them from squeaking and rubbing.
The '37-'38's use four cab mounting bolts with springs on them at the rear to let the cab move up and down on the frame as it twists over rocks and bumps, the front cab to frame mounts are the pivot points. I know on these older trucks the fenders are not bolted to the cab for this reason, it would be to much stress on the fenders as the cab and frame twist around. Joe
