Ford 289 DD prop size

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Edub
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Ford 289 DD prop size

Post by Edub » Thu Dec 27, 2018 10:16 pm

**first post** I’ve been running mud motors for the last few years and recently made the switch over to the airboat world as I run much for hard bottom super shallow marshes where the mud motors loose push. Hull is 12ft and unknown make and the engine is a ford 289 with a 4 barrel carb. the Prop that is on the boat now is 68x30 and I’m curious if anyone has any opinion on the correct size. This prop can spin past 3000 rpm which after reading into it is a problem. The boat runs great I just feel like I’m missing out on a lot of power in the prop.

SWAMPHUNTER45
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Re: Ford 289 DD prop size

Post by SWAMPHUNTER45 » Fri Dec 28, 2018 7:48 am

Welcome to Southern Airboat! With props it is three things to look at the length, width and pitch. It would be really nice to try a short Sensenich Q blade on it or the new JM series of blades where you can adjust the pitch to put it exactly at the 3,000 rpm mark. A 69 inch 2 blade JM would be interesting to test. Over spinning a stick (wood) prop is a huge safety concern especially if it has been weathered. When a prop fails it basically happens in an instant and becomes a bomb sending fragments. I would be trying to find someone with a carbon fiber prop to test. Where are you located?

Capt steve
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Re: Ford 289 DD prop size

Post by Capt steve » Fri Dec 28, 2018 10:08 am

Wow a Ford 289 with a four barrel. Add an eddlebrock high rise manifold and you have my first car. A 1965 mustang coup!

That just brought back memories.
100 ton master captain
Professional airboat operator
I made enough money to buy Miami,
But I pi$$ed it away so fast

JLP3314
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Re: Ford 289 DD prop size

Post by JLP3314 » Fri Dec 28, 2018 8:45 pm

Member Uncle Bubba spun wood on his 302 for a few years he might be able to help. :thumbleft:
:happy1:
Don't waste your time-its the only thing you can't get back, (Cntry141IQ/John had another thousand of these before he went sliding into the sky). :-(

hdsadey
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Re: Ford 289 DD prop size

Post by hdsadey » Fri Dec 28, 2018 11:04 pm

I've been running a 302 with a 72 Waterwalker Sig Series for years. Pitched it to turn 3000 wide open, probably close to the 2 mark. Did ok with it, stopping on anything not slick was a no no! The new 408 I built should be a monster in comparsion.
02 Predator 12' 0320 Lycoming
92 Big O 13' Ford 408 Windsor DD Dry Runnin MOFO!
99 Donzi 16 Classic 350 Vortec

Edub
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Re: Ford 289 DD prop size

Post by Edub » Sat Dec 29, 2018 12:36 am

So should I be looking at a longer prop or one with more pitch?

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Deano
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Re: Ford 289 DD prop size

Post by Deano » Sat Dec 29, 2018 7:45 am

Generically, when all other things are equal, diameter trumps pitch.
Given the subject engine and power level available @ 3k rpm, the difference is not worth getting a heartburn over, though.

Still, with that having been said, a little longer would most likely be preferable.
If at all possible it is nearly always recommended (when finances allow), to go with a carbon fiber prop because they are adjustable.
You don't want to finally find the perfect wood prop and then make an upgrade or switch engines and have to start over because you are over spinning it. With an adjustable carbon fiber, you just add a little pitch and go on your merry way.

It is worth noting that the Signature blades (my recommendation as well) end up making a 72" prop w/a medium hub.
Consequently, using a short hub will render the prop being 70" so either would work, depending on what crosses your path.

You should do as Swamphunter suggested and add your location to your Profile, so people know where you are.
Somebody near you may have a prop you could test and either confirm of deny the fitment of whatever it is that they have.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan

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NorthWestFloridaBoy
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Re: Ford 289 DD prop size

Post by NorthWestFloridaBoy » Sat Dec 29, 2018 1:57 pm

Yep, definitely get an adjustable composite prop. Run that 289 till it blows then throw a 351w on it, adjust the prop pitch and enjoy the bigger engine and increase in performance. Go with at least the 72" or you'll regret going shorter in the future when you have more motor. He'll I've even heard those old 300 I6 motors do good on boats.

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