I bought a Smith Miniplane with no engine. The details from its past are scattered between the logbooks and letters from the builder and subsequent buyers. As far as I can tell it was built and flown in 1971 with an O-235. At some point it got an O-290G and then in 2007 it got an O-290D. Now I have installed an O-235 again. I think it just needs a logbook entry but I have had people tell me it may have to go back into Phase 1. Not sure why that would be since it was built and flew off it's 75 hours with an O-235. I'm not gonna bother the FSDO if I don't have to. What would you do?