First, I would definitely recommend a stainless steel prop. They are much more efficient that the aluminum ones (albeit, more expensive). I am more familiar with the props out there for V-6s, but Merc makes several props for your engine. Best top speed and best hole shot are almost impossible to have together, so you may need to compromise one for the other (at least a little bit, anyway). However, compared to that aluminum prop, you may be able to find a prop that does both better than what you have now. I would go to a three blade if you want best top end and a four blade if you want best acceleration and load carrying ability. Get a copy of Hot Boat magazine and call some of the companies in the back that advertise props. They will make specific recommendations. Also, Merc now has a set of props that you can try before you buy (they are painted blue). Ask your local Merc dealer if he participates in that program. You may be able to stay with about a 19" pitch prop since the increased speed of a stainless should actually help you to get some "free rpm". Only way to be sure, however, is to try. For best acceleration, a 17"-18" four blade (properly selected) would really rocket you out of the hole and maybe still give you more top end than your current aluminum. Good luck!