Hi Max,
I still pick up the occasional F/C, but I don't actively go hunting them these days. I have only built the one PT on an early base and that is because I picked it up with the slide plate modified to take the PT. I have kept pics and drawings of it just incase I have to build one at a later date when I have no F/C's left here. The one thing that might make the F/C's hard to come by is the lack of pull starters, both the cup type and the sidepull. I have probably over 50 tested PT's here and probably another60 that have been straight fueled or would not run for some reason. If supply dries up I can start to re-ring some of those in the future. If I had to use the adapter plate, that lifts the motor nearly 20mm so that means I couldn't use the standard PT pulley because it will run the belt 20mm too high I have to come up with a different pulley design for them. I do have the idea worked out I just have to find a pulley I could use to make it work. I doubt anybody would bother looking at the pulley underneath, most people just want these to work and start easily