I pulled this engine out of the drawer and decided to chuck the stock ring and put the Bowman ring in it that I had. After 2 tanks of FAI fuel and 3 tanks of 5% nitro fuel, I peaked it for just a second to grab a tach reading of 14,100rpm on a 12x6 APC and red Jettstream .90 muffler. After another 5-6 tanks, I'll see where it ends up. So far it's +200rpm from the stock ring and it runs fantastic. Better than it did with the stock ring and it's not even completely broken in yet. I look forward to seeing how it runs after its more broken in.