I have a new stainless 13.75x15 hubbed Merc if you figure out that is the one
for you. It is a bit too much prop for a 60 big foot on a 20' Harris pontoon so
it might be close for you.

I topped out at about 5100-5200 with it.

make me an offer.
http://members.aol.com/gfretwell/ssprop.jpg