Thanks Brit, My numbers with the stock baffled muffler and a ProZinger 12x7 running on Fox 5% nitro are as follows
With a ? #3 plug 10,323 rpm
Fox idlebar plug=10,531 rpm
Fox Miracle plug=10,691

The head being cocked, it happens, I fried the piston ring in a black Merco .61 because of that very thing. Like a Moron I gave it to friend who discovered the head being crooked and got a ring from Frank Bowman and now he has fine engine that he flies a lot.

His cylinder liner should be lined up OK, it has a cold rolled steel pin in the block that indexes a notch in the liner phlange.

Dar, I will look and make sure this is the case.