Vee drive or Dana outdrive? What size shaft? If Dana I assume tapered shaft as I believe all splined were aluminum.
Make sure a 12 pitch is what you want as a 12 pitch prop was usually used in single engine configurations and work boats. A 16 pitch was more common. I would pull the prop on your boat and match it if your getting the proper WOT RPM.
http://www.deltaprop.com/props2.asp?cat=5&catname=Aluminum%20Sterndrives Delta is a good source for used props.
NOTE: Most DANA branded props are aluminum with splines.
There should be a model# stamped on the hub also a Mfg. Id. like Michigan Wheel. Most brass props used on Dana outdrives (models 81/91)were made by Michigan Wheel
Suggest you also put this post in classified.