Thanks to Carscw for his suggestion that I shorten my Snapper RER. 2 or 3 weeks after he reminded me of that feature I stood the mower on its tail and took a good look at the spacers and decided it was something I could do. I removed one spacer and the front half of the mower dropped down just by the thickness of the spacer. Then I tightened it all back up and sat it back down on all 4 tires and cranked it up and there was enough slack in the belt for the thing to operate as it was supposed to. So now I know that the 72" Oregon belt (P/N 75-073) will do the job. Eventually the belt will probably stretch enough to cause too much slack, to a point to which the blade may not engage at all and when that happens I will raise it up again and reverse the procedure. I will reinstall enough spacers to correct the slack in the belt and the old Snapper will once again work properly.
These Snapper RER mowers are amazing in how simple their basic design is. Whoever originally designed it created a lawnmower which, if owned by someone has the ability to properly maintain it, can be used for decades. I retired a 1984 28" RER 2 years ago and replaced it with a 1992 33" RER after a total refurbishing for a total investment of around $300.00. I had bought it with a blown engine for only $100.00 including new bags and then spent about $200.00 to re-ring my 12.5 hp Briggs and then purchase the parts needed to do the complete refurbishing. I could've taken it to a shop and spent $500.00 to $700.00 to get the same thing done.
Thanks again Carscw for waking me up and thanks to LawnMowerForum.com for providing us the space to do what we love to do.
valveguy