I see that I should have asked more questions. For example:
1. Can you retrofit a 425?
2. What would it cost?
3. Can you retrofit a 422?
4. What would it cost?
5. Does the 422 gasoline engine have enough power to drive the bigger motors to full torque?
6. Who makes the motors and can we buy them directly from the manufacturer and at what cost?
7. Are the mounting plates the same for old and new motors?
8. Do we really need it, or are we just being greedy?