The 7490 has a bindingless board which is tapered on all 4 sides. Palm position is placed about 3/4" high of center to put more board below the hand for better reach. The side shield has a wider opening for the stick, and it also has an extra blocking rib at the base of the shield to help seal the blocker to the body. This blocker can be customized through the Custom 7-Series program.
The 7460 also has a bindingless board, but it's much thicker and only beveled at the front and back. It has a flat side shield with a much more narrow opening for the stick to provide more protection to the fingers. The flare at the top of the blocker is also a bit more pronounced. Finger protection and palm are identical to the 7490, though on the 7460 the palm is centered on the blocker board. This blocker is not customizable.
Hope that helps.