European engines to this day rotate clockwise whilst American engines rotate a.c.w.- I do not think there is any reason for this except custom and practice.
American engines have the output, ie the propellor, on the business end of the engine in the same way as automobiles have the transmission. The result is that their engines are installed backwards in comparison to British engines. On the big Wright Cyclone or Pratt & Whitney twin row radials the rear bank by the firewall have the low number cylinders so the engine rotates clockwise looking from the rear.