The only purpose for that PTO was to drive a snowblower, as far as I am aware. Even then, the PTO accepted a driveshaft that went between itself and the snowblower. i don't recall ever seeing a PTO for sale as a separate item. They came with the snowblower when new and the same usually holds true today. Nonetheless, I'm sure that one of our members will be able to provide you with the dimensions you seek.