I don't have any experience with that machine and wasn't aware that it could only use 550mm blades.

I don't think that 25mm will make a great difference but, you will have to do some tweaking of throttle curves to keep the head speed down.

I have a friend that put a 46 in a Raptor and left the 550mm blades on it. It may be geared differently but it took lowering the throttle curve quite a bit to get the headspeed into a reasonable range.

Let us know how you get on with it.