I totally get the challenge of hunting down original parts for a vintage tractor like your 1990 Ford 1720, especially when you're keen on keeping everything authentic and steering clear of aftermarket parts. I had a similar issue with my old tractor, needing specific parts that seemed almost impossible to find due to all the mergers and brand changes over the years. After a lot of searching, I stumbled upon this website that became my go-to for genuine parts. This site proved invaluable for me, offering a wide selection of original components, including those tricky ones like the pilot bearing, throw-out bearing, and clutch alignment tool you're after. If you're still on the hunt, I recommend checking out websites that specialize in tractor parts.