The cub will fly with a wide range of motors. A 4c means four cycle and 2c means 2 cycle ( 2stroke). 2 strokes make more power for there size and cost less, but 4 strokes sound better and use less gas, and swing a bigger prop which means take off and climb better. All that being said most cubs that size use a 4 stroke. I fly mine with a saito .65 4stroke and it has plenty of power. Any thing bigger is a waiste unless you will shorten the wing and modify the plane for the bigger motor, and there are better planes than a cub for that type of flying. If cheap is your goal, use a .45 2 stroke, other wize a slightly larger 2 stroke ( 50-65). Just my opinion, others may differ
Mike