Otto - If you read the entire thread you’ll see there is some conflicting information on the flywheel ring gear measurement (seems to indicate a 139 tooth flywheel which would be correct for an original ‘54 3600), but his existing starter is a 12 volt model originally used in ‘55-‘59 trucks. Which evidently worked for years without the grinding expected from a mismatched starter drive and ring gear.
For me, if it worked properly before and just needs a refresh, that’s more likely to be a less expensive solution that results in a known previously working unit back in service.
