Outdrive Fitment Question

SNSTER

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Aug 1, 2011
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I have a boat I am planning on restoring with a whole new driveline. I have already Installed a new built 383 stroker some time back. Now wanting to do a full restore with a new updated outdrive. My question is the boat currently has a Volvo 280 on it. I am considering changing that out to a volvo penta Cobra SX. Will the hole in the transom be the same size for both outdrives? I know the transom plate and everything will have to be changed. This might be a silly question or just some wishful thinking on my part. Thanks

D.J.
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,584
Re: Outdrive Fitment Question

The hole that you have is bigger. If the drive that you have is working, I would stick with it. Those 280s are awesome drives.
 

SNSTER

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Aug 1, 2011
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Re: Outdrive Fitment Question

One I dont think it has the gearing I need. Trying to get this boat into the 70 mph range and its only in the mid 50's with a 23P prop. I have had several problems with this outdrive already and would like the reliability of a newer unit. Parts are also very expensive for it and hard to find.
 

bruceb58

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Re: Outdrive Fitment Question

You are talking about rebuilding your transom to use a newer drive though. Not an easy task.
 

SNSTER

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Aug 1, 2011
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Re: Outdrive Fitment Question

So if I rebuild the 280 is there a way to change the gears in it to make it more desireable for me to use?
 

bruceb58

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Re: Outdrive Fitment Question

That is a DonS question as I am not sure if those are in the upper or lower. What size boat is this on?
 

SNSTER

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Aug 1, 2011
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Re: Outdrive Fitment Question

Pretty sure they are in the lower. Its a 24' and ugly hence the restore lol

IMG_20110801_125822.jpg
 

sqbtr

Senior Chief Petty Officer
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Feb 23, 2010
Messages
716
Re: Outdrive Fitment Question

They are in the lower, show a pic of that sweet 280T
 

sqbtr

Senior Chief Petty Officer
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Feb 23, 2010
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716
Re: Outdrive Fitment Question

+1 on the DP
 

SNSTER

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Aug 1, 2011
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Re: Outdrive Fitment Question

Ok so what is the best way of going to a duoprop on this outdrive? My other boat has a DP but it has a b3
 

SNSTER

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Aug 1, 2011
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Re: Outdrive Fitment Question

Anybody have any ideas on the DP or gear change?
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
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62,321
Re: Outdrive Fitment Question

You can change the lower unit to change to a DP. They are so much better than the Bravo III drives you won't even believe it.

conv.jpg
 

SNSTER

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Aug 1, 2011
Messages
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Re: Outdrive Fitment Question

I was hoping you would chime in Don. Exactly what is the advantage to the duoprop vs. a single? Is it just the better maneuverability? What gear ratios are available in the DP? Hope you dont mind me picking your brain
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
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62,321
Re: Outdrive Fitment Question

Small blocks run the 1.95, big blocks normally use the 1.78.

The DP's are only rated at 50 mph drives, I know of a few in the low 60's. 70's ????

25% better efficiency, fuel milage, and getting on plane, better control. Other than that, they are about the same as a single prop.
 
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