We recently added the Surefly to our 1967 F model. We are still experimenting with LOP operating which we were very hesitant to try before. At altitude running 100 ROP it seems our cylinders & oil temps are elevated more than usual and enriching the mixture running extra rich doesn't seem to help with cooling like it used to. Running ~50 LOP the engine seems to be much happier. The cylinders were at least 20-30 degrees cooler and oil Temps 25-35 degrees cooler. The engine ran smoothly & we reduced fuel burn in cruise to 7 GPH at 12000 ft. Flew non stop 5 hours from Northern Kansas to the Houston Texas area and burned only 40 gallons of our 64 on board! We do have a JPI engine monitor to monitor each cylinder, each EGT, and precise fuel flow.
Like I said we are still getting used to it, but I'm really excited about the fuel savings and efficiency.
Oh and it starts like a car now even on those intermediate hot starts. Yes we had it wired to start on both the Surefly and magneto.
