[canyon.classics]

I was told that a car I recently acquired had all correct 930 parts. Everything underneath looks correct, I can see the turbo, waste gate, all correct factory 930 exhaust and parts ect. But the engine number is puzzling. If I am decoding it correctly 64F03953 comes back as a Japan market regular Carrera motor, but the sequential engine number seems too high since according to my red book, it shows only 361 built from Aug 84 to July 85 for the F model year. Its a 930/21 motor. I find it kind of odd that a Japan market motor would make it over into the US. Secondary my question is how much internal difference is there between a 1985 930/66 motor and a 930/21 motor if all the manifolds, turbo, and exhaust were bolted onto an original non-turbo motor? Any expertise would be appreciated...