coming close to 220 hrs in my IV-P with routine LOP as
per the GAMI people but without gamijectors since the
engine is quite efficient with a reasonable spread
between CHT the hottest cylinder being #2. Usually
cruise at 21K to 24K going east and 18K going west, I
climb full rich and 2500 rpm the limiting factor being
400 degrees CHT which I try not to exceed by
decreasing the rate of climb. Once stabilized (I wait
a few minutes and get the trims unloaded ) I go from
27 g/hrs in the fuel flow to 14.8 to 15.0 g/h with the
"quick pull" method and usually end up with 4-5 knots
less at that setting I can go 4.30 hrs  showing 240
kts as average KIAS with TIT2 at 1640 to 1650. If the
TIT2 goes up I lean more my EGTs usually go 1540 and
quite even CHT;s in the 340 to 350's. My oil
consumption has been stable, my plugs are clean and
the engine behaves quite well after more than 200 hrs.
I usually fly long trips and avoid short hops.
so if you are afraid to try, maybe there is some truth
behind all those guys from Ada OK
andres
18AK still going