I recently rescued a Cub with a C85 that had a fresh O-200 conversion. Sadly, I've discovered it has a -8 case and thus cannot accept a starter, which after a total right shoulder replacement and a scheduled total left shoulder replacement a necessity, since I can't convince my lovely 5' bride to sling the prop. I'm thinking perhaps swapping for a C90-12, using Paul Babcock's STC SA00270BO. I've found where our current McCauley 1B90 CM7146 is an approved application, so that helps. Here's another potential snag. I've stumbled upon the possible find of a RR C-90, I think -12, and thus eligible for a B&C starter (?), but other than a research document that specifies, "...the Rolls-Royce versions are "directly interchangeable with the equivalent models manufactured by Continental,"" I cannot find an FAA approved statement of interchangeability. Thoughts?