just wondering what the correct prop would be... right now it has a 13x19 alum prop with WOT it runs about 32 mph at 4000rpms any suggestions? would like to get more speed. engine is in great shape. it is on a 1994 glastron ssv170. me and the wife is about 400lbs plus the actual weight of the boat.. any help would be appreciated.. thanks.. the website says recommended rpms is 5000-5500 WOT