That'll be a clamshell I guess? - Wrap around cowl wit ha front panel pops off to reveal the catches for the main cowl?
This is entirely from memory, but 13 spline shaft, diameters go from something like 11" up to 11.75"
What it's pushing will dictate the pitch. (and to a degree the diameter)
A Yam K series should fit - IF you modify the locking arrangement!
Joking aside, unless you seriously modify the locking, you'll need a merc prop. Those engines used a lockewasher that engages on 2 pins on the back of the prop hub & bend round the faces of the nut. Almost every other O/B of that size range uses a hole in the shaft and a split pin through a castelated prop nut.