Now this gets interesting with a flywheel forward motor installation!
I have a LH (standard automotive) couterclockwise rotationg small block Chevy motor in my 1956 Chris Craft Sportsman, but I am running a RH prop because the motor is flywheel forward and the transmission is running off the front of the motor opposite the flywheel.
If you have any doubt, go take a look under the hood of a motor that uses a belt driven fan (in a traditiional rear wheel drive application), you'll see the fan direction is pulling air toward the motor, and the blades give the story that they are turning counterclockwise in order to do this, when looking from the drivers seat.
Bottom line:
LH is standard counterclockwise automotive rotation (when looking at the flywheel)
RH is considered clockwise "opposite rotation" (when looking at the flywheel)