View Full Version : prop question

02-13-2011, 07:15 PM
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.


02-13-2011, 08:22 PM
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.


Sweet little 16
02-14-2011, 08:52 AM
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.

02-14-2011, 03:45 PM
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

02-14-2011, 04:56 PM
Volvo shaft dimensions for future reference.