All right! Something seemed to help, first I drilled the exhaust opening to 9/32" was less than 1/4" before, plane seemed to fly faster, then I moved the spray bar back, seemed a little faster. I did all that before borrowing a tach to verfy rpm increases. Removing glow plug gasket seemed to lower rpm a little but that was with an idle bar one, removing head gasket got highest reading 12,700, but I could see it leaking, so I put it back. I still need to try OS#8,and a McCoy mc-59, I wonder how much that will be worth? So far, looks like about 12,500 on the ground is best, any comments? I don't know how much more to drill exhaust outlet, spray bar is about 1/4 in, and that is also with 10 percent fuel, need some 15 or so too. Oh, and we have to use a stock MA 10x6 prop.