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Discussion Starter #1
I was talking to a neighbor at the river this past weekend. He seems to know his stuff. Well i was talking about how to get some more speed out of my boat and he had mentioned that replacing the lower unit with a shorter unit would give me a pretty good increase at the top end.

I have been doing my research to see what motor mods can be done but it seems like there is more potential and cost effective ways to getting some more speed by upgrading the out drive instead of the motor.


What do you guys think of this. And what gains are reachable by upgrading your outdrive.
 

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one or two inch imco shorty will would work good. This will produce less drag and more speed and usually you will be able to run a larger prop pitch also depending on what rpm's you were turning prior.
 

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Discussion Starter #3
with just two people in the boat i can hit the factory rev limiter any time i want to.

How would i figure out if i wanted to go with a one or a two inch shorty?
 

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If you get a 2 inch shorty and it's to much you can get a 1 inch spacer pretty cheap.
Sounds like you'll need a bigger prop too.
Just my 2 cents...
 

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Discussion Starter #5
how do you know if 2 inch is too much?

sounds like this is going to be my next mod. Ya i know for top speed i could probalby go up a size on the prop but right now my mid range is awesome and that is where i use the boat most of the time so i went with a labbed and cupped 26p. works great and i dont really have any complaints about my boat. I am just retarded and want to screw up a good thing by trying to go a little faster. plus those lowers look way cooler.
 

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You won't know if 2 inches is to much until you try it, or find someone else with your exact set up that has already tried it. That's why I said get a 2 in then you can get a 1 inch spacer if it is to much.
With less drag your boat should go faster, if you're already on the limiter you will need a bigger prop or you're not going to go any faster.
 

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Discussion Starter #7
i know i will have to step up the prop. I did a lot of prop tuning with cutting edge propellers to get the one i have on there now. What i was wondering is how do you know if 2 inch shorter imco is too short? what does the boat do. does it air out the prop and start slipping? Or do i just keep a close eye on the speedo. if i am going faster it is working if it goes slower it is not?

I have not seen any posts on here about this. You would think there would be more but a search only shows a few of them. There are like 7 boats in willow valley that are just like mine. I am going to start payin attention to see if any of them have a modded lower.

Thanks for the insight. Myabe i should call placecraft as well. If someone has done it on one of their boats i am pretty sure they might know about it.
 

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If it's to high the boat will cavitate real bad getting on plane. I don't really think you can get to high as long as you have water pressure and can get on plane.
My propshafts are 1 1/2 above the bottom of the boat.
 

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Discussion Starter #9
thanks for the info.

My other questions are is IMCO my only option for lowers?

Where do i get them from? is there a guy everyone goes to for these?

Do i buy new or look for a used one?
 

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Imco or Sportmaster... I can't tell you which is better though.
I see them for sale used on OSO quite a bit, otherwise from Imco or a Merc dealer.
 

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Imco will be cheaper and it is a proven lower to be fast. Usually when you go up on the lower as in -1 or -2 or -3 shorty you will up size the pitch on the prop any where from 2-4 pitch sizes and could be more depending on how the boat reacts. You could notice upwards of 3-7mph or more depending on what you do with the combination. Bring up the drive as high as possible as long as you can get it on plane without blowing out the prop. When shorter you will likely spin a little higher rpm getting on plane than a standard lower, this is normal.
 

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Sassy Bull
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Affect on waterski or wakeboard?

I have a 26ft. LaveyCraft Nuera. It has a stock 496HO and Bravo 1 drive. I plan on power upgrades to the 496 at some point.
Before I do that I plan on upgrading the outdrive. I like the idea of a shorter lower unit. More for top end and cool factor than anything.
My question is whether this will have a negative affect on being able to waterski or wakeboard. It does not have a tower. Any input would be
much appreciated.
 

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I have a 26ft. LaveyCraft Nuera. It has a stock 496HO and Bravo 1 drive. I plan on power upgrades to the 496 at some point.
Before I do that I plan on upgrading the outdrive. I like the idea of a shorter lower unit. More for top end and cool factor than anything.
My question is whether this will have a negative affect on being able to waterski or wakeboard. It does not have a tower. Any input would be
much appreciated.
If you still want to wake board or ski still then swap it for a standard lenght imco SC lower, still will pick up mph and not affect skiing fun, you may even be able to go 1" shorter but more than that will jeopardize that.
 

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Discussion Starter #14
I have only pulled skiers a handfull of times with my fun boat. I have a jet ski that is used for that kind of stuff.

I am really liking the idea of the 2 inch shorter drive. I am going to take some dimensions this weekend to see where it sits on level ground.

Another PB member has notified me of a 1 inch shorter lower that he will let me try/sell me. but i dont want to have to buy two. I want to get the right one on my boat from the get go.
 

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Sassy Bull
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If you still want to wake board or ski still then swap it for a standard lenght imco SC lower, still will pick up mph and not affect skiing fun, you may even be able to go 1" shorter but more than that will jeopardize that.
Thanks for the reply and advice.:))THumbsUp
 

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27 Victory 800efi
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I have only pulled skiers a handfull of times with my fun boat. I have a jet ski that is used for that kind of stuff.

I am really liking the idea of the 2 inch shorter drive. I am going to take some dimensions this weekend to see where it sits on level ground.

Another PB member has notified me of a 1 inch shorter lower that he will let me try/sell me. but i dont want to have to buy two. I want to get the right one on my boat from the get go.
Always go shorter at first. Its so much easier to put in a spacer to move the drive down than to buy a -1" lower then realize you want a -2.

Let us know where the center of the propshaft is in relation to the keel.
 

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Discussion Starter #17
I have been trying to get that information. but We have a new baby at the house and i am building a mini boat and i just picked up a 1977 FJ land cruiser. So i have been busy as hell. We are headed out to the river in october at the latest i will be able to get the measurements then
 
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