My 200 has a IO 520 engine. I normally cruise with fuel setting LOP. I have a EDM 700 installed so I can see exactly when I reach peak and GAMI plugs installed so all cylinders peak close to the same tempratures. I think this equipment is important for lean of peak operation. I continue to adjust lean of peak until I fell rougness in the engine. I generally can not get 50 degress lean before this occures. Although I do not reach 50 degress lean of peak, the EGT and cylinder head temperatures remain well within limits. My engine has 750 hours operating in this way and still has good compression tests during each annual.
With cruise around 8000 or 9000 and 2350 RPM I will indicate around 150 to 155 mph depending on weight and density altitude/temperature. This equates to around 160 knots true airspeed. The fuel flow is around 12.3 GPH at 8000 and 12 GPH at 9000.
