Deere 310 series, timing gear turning mechanism

It's time to set the valves on my old 310 (n B, C, D or Z - just an old 310). Cranking the flywheel around is a POA and a slow, knuckle scraping exercise.



I have heard referenced a turning gear that fits into the timing cover hole. Anyone know what the JD special tool number is, and better yet, where to get one?



Thanks

Deere 310 series, timing gear turning mechanism