I had already gotten a slow start on the FT500 project, so your thread gave me a much needed kick in the ass. Henry's widow graciously gave me his hot-rodded XR500 motor. After seizing the stock motor, trying to out-run a pissed off truck driver on I-5, (by roosting him when merging onto the interstate from the dirt shoulder with the front wheel pointed in the air) he threw the White Bros catalog at it: high compression piston, cam, Super Trap exhaust, and bigger carb. Those changes REALLY woke the motor up!
I've gotten the FT motor started, and it runs OK, and is in good shape, but the last time the XR motor was run it was burning oil. I think I'll start with the cam and carb and see how it runs.
The swing arm needle bearings on the FT need to be replaced, and of course the brakes need attention. All things considered, I should be able to make the FT into a "budget racer", if there is such a thing.
Also, 754 Frank has me thinking more about flat-track these days.