Re: 1984 9.8 Merc propeller
try posting this in the propeller forum you will get more and better answers.... also tell em what boat it is going on, how much it weighs, and

how much of a load your going to put in the boat regularly.
in example, 9.8 merc, 14ft jonboat with 36" beam (or 48"), weighs 450lbs ready to go, two people 375lbs and 115lbs... 50lbs of fishing tackle.
that helps them alot.
oh and how many RPMs your currently pulling, what prop you currently have, and what your GPS'ed speed is.