The 70 ces short shaft is a factory made race-spec motor out of South Africa for races such as the Trans Agulhas. I'd hazard a guess at saying that there would be no more than 50 originals or so floating around world-wide. It's a pretty serious bit of kit, be fair to say it'd have 50% again more power than your normal standard leg 70 Yamaha. It spins the 18p without a worry in the world, no bog into corners, the torque of the thing in comparison to the 50 hp motors can't be compared. The motor was bought off an ex racer from SA who had it on a rib running a a reduced custom gear-set. WHich comes in handy as you've noted when needed to spin such a big prop. Have already had the 24p on the 50 (race sealed) and spun that to 6200 @ ~95 from memory. Lots of fun!