The 82 Sanger Flatbottom I just bought came with a 11x15x1 two blade. I'm running a 427 bbc, 11/1 comp, and pushing nearly 600 hp. I'm not sure of the gears but there is a two speed tranny w/rev in it. The boat hits the rpm limiter (5500rpm chip) really quick with speed topping out about 63/4Mph. It also starts pulling to the left pretty hard at about 55 and up. Real hard if I just let off from top speed. I have a three blade prop also, size&pitch unknown, and it tops out at about 68mph also hitting rev limiter but not nearly as fast. It pulls a lot less to the left then the two blade and feels generally smoother. I'm interested in increasing top end as 64 seems too slow for the HP being generated. I'm going to up the rev limiter chip to 6k/6.2k/6.4k rpm, but I'm wondering if I need to look for a larger prop to create more top end? I'm fairly new to all of this so be gentle .