toodogs,
It is very easy to understand this duality: a knowledgeable engine man will tell you to run the engine at 100°F ROP for best power, and at 25-40°F LOP for best economy.
Because cruising at 100°F ROP will give very bad range, the airframe manufacturer will recommend so-called 'best economy' at 25°F ROP, which the engine man will say is the worst place to run the engine with the highest CHT.
Another very significant advantage of running LOP is that NO carbon monoxide is produced, so leaking a exhaust system will not kill the pilot.
My experience with LOP has been very positive, I only wish that the equipment (GAMI, JPI, information) would have available sooner.
The real research in piston engines is no longer in the TCM or LYC faxtories but happens in a small three letter town in Indian country. Pretty soon we'll be able to replace our magnetos with interactive reactive electronic ignition with variable timing in function of the combustion event, permitting the use of unleaded fuel, or autogas, even in high powered turbocharged engines.
Places to visit:
www.avweb.com : columns: all of John Deakins articles on engine management,
www.gami.com If you want to talk to the real experts:
www.avsig.com (maintenance and aircraft).