I have just over a gallon of Avgas through the engine now since the sealed bearing change Todd made to my #1 engine. The sealed bearing (additional crankcase packing) and the move to leaner Avgas running has made the engine purr. At least as strong as before the change but much quieter.

At the contest this wekend a few folks actually noticed the quietness of the set-up and commented on its stronger power output. Have stayed with the 16x12 APC. I briefly tried the new MDK 18.75x10 but I could hear the engine sag, especially towards the end of the run so I went back to the 16x12