Prop options for a park 450

[Toonamelt]

I'm converting my Hobbyzone Super Cub and putting in a Turnegy Park 450. The recommended prop sizes for this motor are 9 x 5 and 8x 4.3. Just wondering, can I try any other sizes with out causing serious damage to the motor? Like, if I wanted to get more torque, could I use a larger prop with a lesser angle... like a 10 x 4.7? Or if I wanted more speed could I use a 8 x 6? I'm not clear if you can mathematically stray from the recommended props for EP motors at all.