The mounts would be the same, but I think the electrical would be different. I know that the rappy has a different electrical harness and cdi than the warriors, so you might have to replace the wiring harness with the motor.
I doubt it would be the same for a 660. They are water-cooled for one thing. And I know for sure that the nerf bars on a 660 are bigger than on a 350 by a couple of inches or so. You could make it work I'm sure but I think it would be a major project.
the 660 motor is taller than the 350 motor, so I don't know for sure that it would even fit in the frame without modifying it. There's only a couple inches of clearance between the head and the frame with the stock motor, so it would be really tight if it did fit.