In orlando call JC Stanley he has plenty of cams and can get a high perf. regrind for a 520 his # 407-927-9701 He is usually in his shop on saturdays also
Try D&S cam in Edgewater. I bought a NEW cam from them for $160. It had failed aircraft specs by .001 on one lobe when they built it. Which made it junk to an aircraft ,but a dream for an airboater. They make cams for aircraft and sometimes have a few that fail specs and they let go cheap. They are also a great bunch of guys to deal with.