Mostly depends on what you use the boat for (tubes, skiing, cruising) and what you want out of the motor-quick hole shot, top end, and typical load. I have a 2008 1900 SR 3 with same power and it came with OEM 3 blade, 23p. At WOT I am at about 4600RPM (range is 44-4800) and get 52mph on GPS with medium load. Am please with time to plane too. Hope this helps.
Same admiral since 1973
New Boat 8/13/11: Chaparral 206SSI with 5.0 VP GXI SX
Prior Boat: 2008 Maxum 1900SR3, 4.3L V6 190HP, Alpha 1 (great boat)
2010 Ford 150 XLT Super Crew 5.4L V-8, tow package
2008 Infiniti G-35