Hi Brendan;
You’re probably not going to like this news but these are becoming scarce.
I did Google “O-200 crankshaft” and got this FB site:
https://www.facebook.com/serviceableaircraftparts/photos/a.523526317809171/523526241142512/?type=3&paipv=0&eav=AfbuT6uvz4XVV3-EHePLqYnlfiSFUkNQU5WGcXX_jQc1Qh9hlRD5797HM1uFH8nSCRQ&_rdr.
Let me know if that works, or what you eventually found.
STeve




