Hiya Jabba. I should clarify that FF is 27 GPH total ie 13.5 GPH /side, and done without GAMIs. Can't get it leaner without roughness. Owner isn't inclined to spend more just now (see below re autopilot).
I'd love to see dyno data on this engine. This plane is an early-ish Mike Jones 'Lock & Key', so apart from the Colemill mods, it had an expensive restoration from Mike Jones. It was done before glass panels became common, so still steam driven gauges (except it has a nice King EHSI that I rather like). It has 530 & 430 WAAS GPS, Avidyne MFD, XM weather, radar & stormscope so nav. is a breeze. Digital FF + an EDM760 so fuel & engine management is catered for too.
Two biggest hassles are the autopilot & Cyl 3 & 4 run hotter than the others.
Autopilot is a KFC200. Usually a good unit, but 1980 and later PA31s were required to include an accelerometer in the installation. Can't find a replacement for a reasonable price. Honeywell will build one as a special order - for only US$20,000! Used serviceable ones are rare as hen's teeth. We have our eye on one for US$7000...