x2! i have some kohler spare parts, 241, 301, 321 if i recall are all the same and come in two variants deep or shallow. also two different block designs that i know of, some had the engine mounts cast into the block insted of mounting with the pan.Dave... the Kohler K301 12hp is about the longest-standing, most prolifically produced heavy-duty single cylinder ever made. Unless there's something really, really special about your machine, chances are there's a bizillion oilpans out there that'd work.
I have a half-dozen K301's... two in Cub Cadet tractors of the '70's and 80's, and several spares in a variety of conditions. I've seen two immediate flavors- one is the 'shallow' pan, the other is 'deep'. the 'deep' pan is same depth as shallow, but has a recess that protrudes out the bottom that provides clearance for the longer rod dipper that appears on many later K301's.
Which pan does your machine have?