https://www.partstree.com/models/ch20-64610-kohler-command-pro-twin-engine-made-for-toro-20hp-14-9kw/02-crankcase-1/
Kohler CH20-64610 - Kohler Command PRO Twin Engine, Made for Toro, 20hp, 14.9kW 02 CrankCase Parts...
02 CrankCase diagram and repair parts lookup for Kohler CH20-64610 - Kohler Command PRO Twin Engine, Made for Toro, 20hp, 14.9kW