Early 70's on manufacture. Don't have exact year. We got out of flying for a while between early and late seventies and he had it before then. He used an OS .40 of the same vintage and it flew with plenty authority. No idea where to get more info. I am sure that World Engines (bought out by ISC and now defunct) carried it. Dad was a World Engines dealer and so we got all of the Japanese stuff through them.