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Discussion Starter · #1 ·
I have 241 1987 Four Winns Liberator
It has the 454 Magnum With a new Alpha 1 drive 1.32 gear ratio
Im running A 15x15 and getting 4400 rpm and 39mph
I tried a 15x17 and a15x19 and it wouldnt plain off. I have soda blasted the bottom over the winter and put just 1 coat of bottom paint. I havent tried it yet. Boat is going back in the water in 2 days. Any help i would appreciate?
 

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U sure thats a true magnum I bought my Libby last year thinking the same thing. It turned out to be a regular 454 330hp u can tell by the engine specs should be located on the valve cover.

If it says 330hp u got a standard. If it says 385hp u got a mag.
 

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IF it does turn out to be a standard 454 like mine was I would go with a 21p Mirage 3blade. Thats what mine had ran great 4500 rpms about 53 top speed if im remembering right.

After blowing my standard 454 late last summer I bought a 454mag 420hp. Also fitted a bravo1 to it.(Which u might want to consider)Shes bad to the bone now. I run a 3 blade 23p Mirage Plus at 4800rpms 61 top speed.

What ever u run make sure its stainless steel
 

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Discussion Starter · #8 ·
On a 23pitch what diameter blade should i be running? I bought a edelbrock intake manifold to try and wake up the motor. should i add it? Is a 23 pitch ok to run on a alpha 1. next year i will add a bravo 1
 

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Is that 39mph from a gps or just the speedo? Sometimes the ole speedos are not so accurate. The speedometer on my 88 201 Lib reads way under, almost 10mph at wot, of its true speed.
 

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Red, go to ur local marina they usually have new and used props for sale, and they`ll let u try them out. Go try a bunch see what works best. I think its best to go with a 21p Mirage. Trust me I had the same set up as you last year and thats what I ran 53 GPS top speed. If you`re not touching that or close to you have other problems then ur prop
 

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SweetEmotion said:
Red, go to ur local marina they usually have new and used props for sale, and they`ll let u try them out. Go try a bunch see what works best. I think its best to go with a 21p Mirage. Trust me I had the same set up as you last year and thats what I ran 53 GPS top speed. If you`re not touching that or close to you have other problems then ur prop
He said he has 1.32 gears. No way will it turn a 21". Never the less he should do 50 or a little better :(
 

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OH then that seems a little weak to be pushing a 241 Libby :confused:

You said u put that alpha on there right? Why didnt you up grade to a bravo then?
 

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Discussion Starter · #14 ·
really couldnt afford the bravo and the sodablast this year. next year ill go with a bravo 1. i have the boat 3 seasons and have dumped 20 grand in it. im doin a lil at a time.
 

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SweetEmotion said:
IF it does turn out to be a standard 454 like mine was I would go with a 21p Mirage 3blade. Thats what mine had ran great 4500 rpms about 53 top speed if im remembering right.

After blowing my standard 454 late last summer I bought a 454mag 420hp. Also fitted a bravo1 to it.(Which u might want to consider)Shes bad to the bone now. I run a 3 blade 23p Mirage Plus at 4800rpms 61 top speed.

What ever u run make sure its stainless steel
SweetEmotion, what was your gear ratio with the old 454? And thanks a ton for recommending the Mirage Plus 21P!!!!! :D For RedLiberators reference I have a 241 LIberator, 7.4MPI (310HP?), 1.5:1 Bravo1, 21P Mercury Mirage Plus 3blade SS. My RPMs dropped from 4400 (with prev 4 blade 21P) to 4250, but my speed increased from 38 to 48. I may a try a 19P Mirage Plus for the hell of it.
 

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Discussion Starter · #19 ·
Took the boat out today and ran it. full throttle and trimmed out i was only getting 4100 rpm with a 15x17 prop. Was wondering if i should drop my diameter to a 14" and bring my pitch to a 21"? I have 1.32 gears in my alpha? does any1 have a idea or some help?
 

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Discussion Starter · #20 ·
Ill have some pics of the boat soon. I dropped 5000 on new bucket seats and a totally new interior. White and red seats with red pipeline.
4000 on a stereo. 3 sets of boston accoustic componets sets. 2 jbl amps. and 2 bazooka tubes.
New 454 , New alpha 1 outdrive, Baking soda blast. red led lights everywhere. Teak burlwood interior cabinets. Stainless steel fridge, and the list goes on. and on and on.
 
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