Update
So I went on an extensive hunt for a stock replacement belt for this saw, and hit ace hardwares, auto parts stores, home depots and even 2 specialized woodworking shops in my area to no avail.
However I did have a brand new pulley and link belt set, so I decided to do this!
It was actually a huge pain in the ass getting this installed and aligned. I removed and re-installed the belt about 50 times trying to get the right balance of tension. I also re-installed the motor several times trying to get it's position correct, and ended up having to shim with washers to correct some warpage to the mount that must be due to the saw's age.
The end result? I still can't cut the damn ZCI. The 10" blade at it's lowest position sticks into the bottom of the cut I made with the 7.25" blade. When turning the saw on the blade is bound so tightly it does not move at all. I tested with the stock insert and had no problem making a 3.25" depth cut into a 4x4, and even ripped (beautifully ripped I might add for a $20 saw blade) a piece of 1 inch thick pressure treated about 24 inches long with no trouble. So the UHMW is just that strong I guess.
Should I try using my full kerf 8" blade? My other two blades are thin kerf, and this would make it not technically zero clearance, but still better at reducing tearout than the stock insert. Not to mention I'd like to get my splitters installed, I was awful nervous ripping that piece without one. Thank god reading this forums has made me anal about adjusting miter/blade squareness and blade heeling.
Also I notice some bearing noise from my motor if I spin it by hand and on startup. I'm guessing that means she needs to be replaced. I've seen some on Amazon (seems to be the cheapest option) and it looks like it's going to cost me another $300 bucks or more! Which would make the total price I've spent on this saw well over $600...Errggg. Any suggestions or better options? Stock motor was 1.5 hp 3450 RPM