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Thread: prop question

  1. #1
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    prop question

    Hi guys
    I have a St Tropez running a 350 chev with a 280 penta, currently using a 16 x 17 VP prop WOT 5500 revs and 42mph, would a 14 x 23 get me more top end and is there any other prop that would fit on a short shaft.

    any help would be great.

    Cheers

  2. #2
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    23 is a major pitch change, that would suck about 1,000 RPM off I would try a 21. At 5500 you are past the peak torque curve, that engine performs better at 48-5000.

    Phil
    No matter what your beliefs are "GOD BLESS AMERICA"

    Fully retired marine tech near 60 years in the biz.

  3. #3
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    dropping 2 in dia. = approx +400 rpm
    adding 6 in pitch = approx - 1200 rpm
    nets you approx -800 rpm which puts you in the 4600-4700 rpm ballpark.

    never seen a 280 with a short shaft, regardless between various size thrust washers, custom fasteners,or drilling and tapping the prop shaft short or long don't matter.

    you need to find out what drive ratio you have also if you're looking to dial this setup in.

  4. #4
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    running a 1.60 ratio, i have been told that in order to get top end speed i need to go to a 16x21, at the moment at 4000rpm i get 25mph great for getting out of the water but no top end, so would a 16x21 do the job? thanks again

  5. #5
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    Volvo shaft dimensions for future reference.


    Jeff
    " Just piercing the surface"

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