Mark, Yes it's the Yamaha racing 70CES short shaft, the same used in S850/F4. Every motor used in Euro Class racing has to meet UIM specs/homologation.
Thank you gentlemen. Some has been asking about running a Merc 650xs or 700x in T-850, but I suspected those motors were no longer allowed because they have been out of production for more than 10 years and parts have not been available for a very long time.
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since 1925 about 150 different models of racing outboards have been made