I done a little research and discovered that I can convert my 2001 Mercury 40hp to a 50hp by changing the carburetors, reeds, and removing the reed stop. It is my understanding that the only difference in the 50hp and the 40hp in that year were those 3 parts. The 60hp is the same also but the exhaust porting is different on it making the swap much more difficult and expensive. I found a guy on a high performance tiller motor page "Ooser Outlaws" that has the three carbs and reed block for sale for $150 plus shipping. He said that he has done the sap before on a 1948 and went from 31mph to 41mph. My boat currently is an 1860 flatbottom riveted hull thats rated for a 75hp max. It runs 24mph with the 40hp (no til/trim) 10.5P prop loaded to fish. Do you guys think that doing the swap would be very beneficial on a boat like mine with all the weight of a bowfishing setup? I know his boat was completely stripped out with nothing but hull, motor, gas, and driver. Mine has generators, lights, fish barrels, 4 guys, 2 champion 2000 generators, 8 250w hps ballast, and other random items. I figure if I could gain 5 mph it would probably be worth it. If I gained 10 then I would be extremely pleased.