I recently picked up an rv 4 already built it was set up with an os .46 I want to put a 4 stroke in it would a saito .56 be plenty of power it said .9 hp while the os I believe is 1.2 hp??? Or should I go with a saito .62 idk what to do!!?? I love the sound of 4 strokes especially in a scale rv4!!

I would personally go with the Saito .62, same size case as the .56, with a little more power.
The difference I like between a 4-stroke and a 2-stroke motor is the 4 stroke has a wider
torque band than the 2-stroke and develops it's max HP at a lower RPM.

I still have mine and it flew GREAT with an OS 52...very scale like so if you wish to do some wild aerobatics, anything larger will get it done!

I like the OS motors better myself but of course this is a personal preference . Saito is a great motor too . I think the OS fs 56 would be perfect

LOL I put a saito .50 in it it produces .05 less hp then a .56 which hardly anything

Flies really well with the saito .50 hey for 50$ for the engine you can't complain right??