Michigan wheel numbers

[PiratePast40]

I bought a prop on ebay but don't know the specs. It matches the diameter of my existing 14", 15 pitch propeller on a Volvo 280 outdrive. The numbers on the prop are: SMC 288. I can't find a reference sheet to match the numbers to a pitch and diameter. Visually, the pitch seems to be the same as the existing prop but would like to know for sure. Google isn't much help. Anyone out there know how else to find the specs? Is there a way to measure the pitch?

Thanks for any help.