So I found that the PO must have painted my original prop pretty heavy and it covered all the stamped numbers, I found where they were to figure out the prop and it is an OMC 763471. 15*15 aluminum propeller.
So I bought a replacement Solas 4 blade(new) and a stainless 3 blade solas(used)
Neither of them fit. It seems as if my original prop has a significantly longer hub. The splines on the 2 new props engage but they are about 2 inches from contacting the thrust washer (at the bullet) before the splines bottom out.
I'm imagining this is incorrect but no matter how much research I do, I don't find anything that a long hub prop exists for this motor and I can't imagine I need a thrust washer that's almost 3" thick.
Any ideas? I'm really at a loss here

Since the old prop did fit those numbers HAVE to be correct. I hate to suggest this, but did you contact OMC with those numbers and see if they have one in stock? And if not, do they have a replacement that will fit your hub. If there's an OMC replacement # than it should fit your hub. Then you can transpose that number to a Solas or Michigan Wheel or whatever. (And I'd see about returning that 4 blade prop [the new one] to whoever you bought it from, explaining that it doesn't fit and that they sent you the wrong prop.) You're probably stuck with the 3 blade since it's a used prop.

I would be checking the splines of your prop shaft for damage. The prop must slide all the way forward to the thrust washer and on far enough so that the prop slides just inside the gear case to seal exhaust gasses. Some props do use a different washer arrangement to hold them on, but to my knowledge OMC only used 1 style prop for the V6 gear case(there was a thrust washer change in 91, but this didn't effect the prop).