There IS quite a variety on what is available with the predefined engines.

You can easily create any engine based upon performance data for a particular engine/motor.

It is quite simple to do. Copy an existing engine that is close to what you want to use, give it a new name.

Adjust the power curve so that the RPM values in the editor reflect what the real engine puts out for a given prop in a static test.
Cut the curve ( make it drop to zero ) at speeds that are too fast for the real engine... and you're done...