OMC king cobra conversion

Noldisx

Cadet
Joined
Mar 21, 2017
Messages
7
Finally, we could not find the reason for the overheating of the OMC 454 engine with the king cobra drive on high RPM. I put a brand new Volvo Penta 5.7 GI into my Chris Craft 282 Crown.
The boat runs good with the same prop previously used on the 454. Just max rpm is about 300 lower.
Next winter I want to replace the king cobra drive against an SX drive.
Anyone got experience on that? Think the king cut out is much bigger?? Is there an adapter plate available on the market? Or do I have to close the cut out completely and make a new one?
Thanks for any comments, Noldi
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,251
Think the king cut out is much bigger??

Ayuh,..... Welcome Aboard,..... As far as I know, both drives use the Merc keyhole, which is pretty much the industry standard now a days,.....
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Next winter I want to replace the king cobra drive against an SX drive.
Anyone got experience on that? Think the king cut out is much bigger?? Is there an adapter plate available on the market? Or do I have to close the cut out completely and make a new one?
Thanks for any comments, Noldi
Yes. If you want to still do a 454, You will have to replace the transom mount, inner transom plate and flywheel housing with all OMC or Volvo 7.4L "stuff" from 1996 or newer if you want Volvo or (OMG) Cobra SX and in a boat that big, I would not use any drive OTHER than a Dual Contra-Rotating prop drive (DUO-Prop or Bravo III)

Go to http://epc.brp.com/ to view part numbers and illustrations. Don't try to find the parts individually, it'll be much easier to find a donor boat with a busted engine and/or broken hull and swap it all over.

If it were me, I would try to find a similarly powered (6.2/7.4/8.1 Bravo) Mercruiser package. When I was looking, I found FAR MORE Mercruiser engines and drives than Volvo.

In fact, I initially tried to find a 300hp (7.4L/8.1) + Volvo DUO-Prop drive package.

During the time I was looking, I found ZERO Volvo packages............and found 5 or 6 Mercruiser 5.7L(300hp EFI), 7.4L (300hp carb) and 8.1L 375/425/475hp Bravo I, II, III packages, $5000-$8500.

I ended up buying the $5000 7.4L + Bravo III package. (I now wish I had gotten the 8.1L 475hp Bravo III package!!)

Good luck!

Rick
 
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