Jerry, There is a company around Monticello that does it. Been told he goes by the 'boat Doctor' or something. Kendall got his done there last year. I have a 25 hp and last year bought a new 4 blade prop for $80. I use my old aluminum prop for the rivers. The 4 blade does a way better job of pushing the boat in tournament mode, with all the extra weight. Get ahold of Kendall he should be able to help you out.