I also need prop advice

[SippyRat]

1st run with my 1987 Diplomat 17'8" 2006 4.3 V6 Alpha One 17p three blade:

comes out of the whole like a rocket but revs way too fast up to 5600rpm @ 43mph

put on my friends 21p three blade ss and still came out fairly quick and reached 53mph @ 5000 rpm

I'm not sure what prop to buy

I too want the best of both worlds but thats impossible. so what is realistic?

I can't seem to find the WOT for this motor, one shop in town told me 4200 to 4800 and another said 5200 to 5600. The motor seems to have a ton of power between 4700 and 5300

I need these specs before I choose a prop

 

[Combat Rock]

i dont think I/Os are supposed to rev above 4800 but i could be wrong.

 

[JW]

My 1995 Persuader had the 4.3 LX 4bbl motor with the Alpha drive and the rpm range was 4200-4800. When I ran the 21" High 5, the motor would sit right on 5000 rpms. A little high, but OK. When I'd put the 23" Laser II on for top speed fun, my rpms would drop to around 4300-4400 but my top end was incredible for a V6...............

If you've got a Mercury built 4.3 V6, then your RPM range is 4200-4800. At 5300, you're stretching it...................

 

[checkmate DOH!!]

what gear ratio is in the out drive??? sounds like the 1.65:1 or like the drive i have in my 85 diplomat 1.84:1 cuz its equipped with the 3.7L mercruiser 470 engine. Try a 3-blade 14.50 inch diameter X 23p aluminum and you should still have a nice holeshot but will find top speed at a more reasonable rpm----you should top out about 4600 or so with the v6---although a run in the 5000 rpm range here and there for a short period probably wouldnt hurt the engine.

steve