if the prop is to much for the motor to handle all you are doing is wasting fuel a 25p 3 blade is easier to spin on top end but gives more slip out of the hole or in a tight turn you can lab finish the 26 p and get 2-300 more rpms out of it

A 25 PITCH MIRAGE PLUS LABBED WILL BE YOUR FASTEST PROPELLER.or try a 24 Bravo-one.

Depending on set up yes this could be normal. It is kind of like over carburating a motor and they get very sluggish or respond to throttle poorly. Kind of like trying to take off or accelerate a car in high gear and low RPM. No power and if you full throttle it will bog down but if you ease in to the throttle it will take off better. Not the best splainen I know.
Try a smaller prop I think you will be pleased with the outcome. Keep us informed and happy testing.
Peformance boating is test - test and more test as for set up. Unless you have the big bucks and go with a known package.

I would prop for 5400 rpm on top end. I think you will be happier than trying to hold it to 5000. I know the numbers but I think with that cam you will have better performance.

yep!!

Crane specs say the powerband for that cam is 3000-6000rpms. Also, with that big of cam, I would run higher initial timing. Would help idling and low end power. You would have change ignition modules to 20* advance one.

I have a smilar engine setup in a 24 Outlaw. 454Mag, rect port heads milled .20 to get 9.0 CR, mag intake, Holley 800, Crane cam #134241(226/236,.534/.553). I ran a 23" Mirage+ to 5500rpms with it. The torque is starting to fall off though. I also ran a 24" Bravo 1 and it is the perfect prop at 5200 rpms.

With that big of cam in a 454, you should spin at 5200-5400rpm at least.

BTW, did you check plug readings after the runs. You could be lean on fuel.

whodathought,

Yes, prop for max horsepower.

What is odd is the fact that you saw a difference of almost 1000 rpm between the 26 Bravo and the 23 Mirage. I would have expected about 400-500. There are many reasons for this. Two of which are, either the Mirage or the Bravo are not stock and have been modified. Or, the power curve of the motor is such that it starting to produce power in the low 5000 range.
What doesn't make sense is that your speed was higher with the Bravo 1 at 4400 than with the Mirage at 5500. Speed comes from horsepower.
I would take a close look at the Mirage and see if it has been worked, if it has that could account for the high rpm and poor speed numbers with it.
Just a couple things to think about.

Matt
Throttle-Up Propellers

Plugs! Read the plugs!
Might be running plum outta fuel. OR might be drownin it...

Plugs are the best way to know.

Only if they look right should you move to the next step.

As far as the timing issue, where you are now should be fine for WOT testing. After you have settled on a prop, etc, you may indeed want to start with more initial timing and use a different module - but it shouldnt make any diff on what youre doing now.

Thank you all for your help. I think first I am going to do is check fuel pres. to make sure my pump is kepping up with my engine. Then I will check WOT carb tuneing I guess by reading the plugs. I used to use O2 sensor with a LED indicator made by K&N on my street cars and bikes. Any thought on those for marine aplications? How do I get it into my fully water jacketed dry system? If all that checks out I was woundering if Houstion prop. could do anyhting with this prop. to make it fit my needs?

Thanks,
Andy

Darin,
Could you give me an idea what can be done to get 600 rpm out of this prop and what am I looking at fo cost? Or is it better to just sell this one and go with a 24 pitch?
Andy

Go with a 24" prop. It will increase your rpms by roughly 400, and probably more since you are getting more into the power range of the cam.
Don't be afraid to spin that engine at 5400-5500 WOT.