RE: converting a 9451 to 9351????
Hi George,
Unfortunatley, the cases, pots and amps are different between these servos and it would not be possible to make the other gears fit.
I hope you find this information helpful. You can also reach our Futaba support technical team at 217-398-8970, or via fax at 217-398-7721.
Sincerely,
Krysta
Lead Futaba Customer Service and Programming Technician