Valve seat is ok and valve seals well - Made a delrin plug and held it in with a 3mm cap screw though the guide. filled the head and small pressure on the port and bubbles showed it definitely coming from the seat /head interface. I think I'm just going to accept the fact that compression is mushy on this one as it runs so well. Might throw rings at it if I find some.

To Bert's item - its amazing what they will run with sometimes - Turbines are even better - we open up our little turboprops sometimes to do "hot section inspections" and find pure garbage - vanes all warped and cracked and eroded blades yet they preform right on the numbers in a performance check. Others that look pristine can struggle to make proper power. Dynamic gas flows can be tricky....