After purchasing a new loader grate and back cut shoe from Jack at MPD, I have made a huge increase in speed. Not to mention the quality of work he does, the loader grate fit to a "T" and looks great made from S.S. The shoe fit perfectly and the machine work is flawless. After following his advise on shimming the back cut shoe down to the keel line, I have made an increase in speed of 11 mph. My 21' Howard with a 468 Chevy and 8-71 Blower looked good on the water at 60 mph WOT but now it is SMOKING at a blistering 71.3 mph. I think there might be a couple mph left in there with my last shim I made at .50". I'll follow Jack's advice on cutting down my A+ impellor to a A- and hope for some more top end. Right now I top out at about 5300 rpm and would like to use the last 700 rpm I have in the power band. Maybe this might bring my speed up to the high 70s and maybe break 80 mph. All said and done I have gained 11 mph for under $400.00