Here's an option. Just the other day one of the guys at Central Cylinder (an all inclusive overhaul shop here in Omaha) was talking about an O-360 he put together for himself, but is now thinking of selling. It has moderately high-compression pistons, typical magnetos, with some nicely chromed pieces. Doesn't sound like much until he tells you how he perfecdtly machined everything perfect, all components balanced to a half a gram and then meticulously put together. Not sure about price, but would probably be in the same ball-park as any of the others. Maybe not the answer you're looking for, but the best engine IMHO is one that is dependable. Best, -Jim