OK, a local guy has a "boat" a pretty good sized cuddy, and his
outdrive is locked up. Well, He found out that it's got an OMC
outdrive. He doesn't know which.

Did OMC still use "Stringers" in 1988? or were they the "Cobra"
drives?

Not sure but could it also be the Volvo-Penta Hybrid?

I haven't been over to see for myself, so my info is quite limited.