Reply to "Photos of the -1 clutch disc?"

THats just a chamfer. Biggest danger is cutting the splined hub down and having the anti-chatter springs or their stamped holders hit the relieved part of the flywheel. On other engine swaps, I've had this happen.
Another danger is from people not knowing that the two discs are actually different: one has a 1-1/16" 10-spline while the other has a 1-1/8" 10-spline. They're only 0.060" different so the larger disc will fit the smaller input shaft but will be a very sloppy, noisy fit.
Speaking of clutch disc problems, one of our mutual friends had the weld break between a factory Pantera clutch hub and the central steel disc, which instantly disconnected the engine from the gearbox! Thats very rare but he has a history of such odd things happening.