I have a nice well used TT GP42 that made the following numbers using an OS .40 size muffler with no baffle (cause that is all I had). On an APC 10X4 15,300 an APC 10X7 11,800. On 15% Magnum fuel and a Merlin red plug. 57 deg temp, 42% hum. 30.3in baro.