The Shark9 is a 3 port engine and it has a balanced crank in it. It also has the much lower cooling head on it so it may run a little warmer.

Shark10 no longer has a balanced crank and they have lowered the exhaust port on it to help with fuel mileage, it is also not a 3 port like the Shark9. It is more similar to the B10

A lot of people think the Cross10 is the same engine as the Shark9 and this is not true either. The Cross does not have the balanced crankshaft in it.