Hmmm....well Tim mentioned a shim for 1954 if a spare was on the bed side. That would raise the driver's side to compensate for weight. If it wasn't sitting oddly with the old springs, I wouldn't think the rears would make a difference. I suppose you could jack the rear end up to the point each wheel was off the ground and set it on equal height blocks. If the front still sits higher on one side, you'll know the problem is in that (or the other) spring but not in the rear.
One of my questions would be "how much extra weight did the side mounted spare add?" If a shim was needed to level the front, wouldn't it have also been needed on the rear?
Jon
