ok. I have a 1980 vintage MC-1 outdrive, SN 5576434. The lower shift cable is done. If I go on Marineengine.com, using that serial number, I get a Sierra P/N 18-2157. However, If I go to the earlier schematics, I get P/N 18-2158 with a note that serial numbers up to 6225577 use the older style...