Needing a new prop for my copperhead can’t seem to find the specs on the stock prop
Diameter and pitch only marking are C-10 on the one I have

Copperhead makes their own props. I have a 23 with a 3/4 threaded shaft and nobody makes a surface drive prop for that size. Only thing to do is contact them for a new prop or get a different motor that has aftermarket prop options.