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I'm trying to figure what might be better prop for my boat and get my head around what is better. I understand that pitch is essentially how far the boat should move per revolution, but how does diameter affect this, and how sensitive are changes to diameter.
I'm currently running a 11 1/2 x 15" 2 blade, which seems to do the job pretty good, although I'm sure there is something that may be better.
My boat is 17'6" V drive flat bottom. 17% in Vdrive. Last engine was 377 SBC. Guessing around 500HP. It used to top out at about 7000rpm down the straights when racing. Shop the prop was bought from said at 7000rpm, it should be around the 100mph mark.
I'm in the process of building a 400sbc for it, that will hopefully go a bit harder. I've thought abought trying a 11 x 16" prop if I can get one. I know that it should move the boat 16" theoretically per revolution, but what will it do going to 1/2" smaller diameter than what I'm currently running? Will it slip more? Will it increase rpm where prop begins to bite? Or would I be better off looking for 11 1/2 x 16"?
 

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I suggest you repost this in the vdrive forum. from what I know with my flat your prop info is pretty good. I just don’t think you will have enough HP to turn a 16 pitch prop even with the smaller diameter. I would like to try a 10 7/8x 16 on my own flat. I am running about 650HP with 18 gears and a 11 1/2 x15 now. I run a pretty solid 95 mph.
 
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