Glad to see you worked it out.

Never Under 9300 rpm????????? I have never heard or seen anyone run a YS big block over 9000RPM before. Does it last like that? The SC was notorious for failures. Maybe you found the answer in using very little pitch. They were of course designed for big pitch numbers?
Maybe SC troubles could have been related to load on the engine?

Great engine for power, I flew one myself 6 years ago. Had the power of a 140 but had to be run very rich or you had Melt down. Many did meltdown, I heard about several supercharger failures. One was a buddy of mines. Never heard a reason for the failures? Any one know why?

Brad