I just put in a high performance 5.7L and have a lot of wasted rpms. I've got the stock 17 pitch and need some ideas on what others have used.

Are you saying you are over reving the prop?

If you could post your performance data, we can take a look at your propellers efficiency for starters.

What is your WOT RPM?
What is your WOT MPH via GPS?
What drive and gear ratio?

With a little information we can get you started.

Julie

Sorry I don't have the gear ratio but I will try to find out.
The engine manufacturer has the max hp rated at 5400 rpms, peak torque at 3700, and cruising range between 4800 and 5200. Dyno was 300 hp. I've put it on the GPS once at it was in very rough water and running about 55-56 mph. If I peg the throttle it will peak out around 6200 rpms but of course i'm just spinning the prop. I still want a decent hole shot but really want the top end speed. Thanks so much for your time and hope all this helped.

What kind of stock 17" prop. Model and # of blades.

If you can spin that prop to 6200 and you wnat to spin 5400, then you would go up in pitch to a 21" in the same prop.

1" of pitch = 200rpms.


thats about the info you will get without some better info on the set up, wot rpms and gear ratio.

Griff thanks for the feedback. I won't be able to get more info until tomorrow hopefully. I'll try to post the rest of the info asap. Thanks again.

I had a stock Mag 350ci F206 LS like 260 hp and was able to spin a 19" Cleaver 4800! around 55-57 mph! Othewise I can't remember if it was a 19 or 21 pitch Rapture 3 blade that worked real good.

I have a friend with a 1989 Formula 206LS.
The boat was repowered with a new 325HP/350 vortec a few years back.
He runs a 21p 3 blade Merc Mirage.

Pier Pressure,

Once you get some new numbers, we can set you up with some test propellers in 3 and 4 blade options. We will need the WOT rpm you can currently run and verify the propeller make and pitch. Let us know if we can help in this regard.

I still have the factory Alpha one drive but I don't know the gear ratio. 6,200 was the WOT and 55-56 was top speed. But like I said I ran 55 at 5400 rpms. I've got a dealer close to me that will let me test them out but I needed to know about where to start. Looks like I'm going to test out the 21 pitch and see how it performs. I've got the high performance 350 which hit the Dyno at 300hp. Hopefully I can get 60 mph out of it with the correct prop. I know without my gear ratio its hard to answer that. Thanks again to everyone!