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  1. #1

    Default OMC king cobra package to mercruiser package

    Hey there. I am about to start a big repower project. Here is some background. I have a 1990 Advantage PartyCat 26'. Powered by a OMC king cobea 454 with closed cooling and King Cobra Outdrive. I also have a wrecked Mariah Shabbah with mercruiser 540 600hp and Bravo with 1 imco lower. I want to repower the PartyCat with the the Mercruiser set up engine and outdrive. both boats are complete and running. The Mariah has a damaged hull.

    OK here comes the questions

    Is the cut out in the transom for the King Cobra the same as the Mercruiser for bravo 1?

    I have heard that I may just need to drill some extra holes. is this true?

    If not is there an adapter plate? anyone have a scorce for one if one is needed?


    Will the inner gimble ring line up with the bell housing of the mercruiser once installed (if the transom cut out is the same)

    Are the steering cables the same?

    My shifter and throttle are offshore controls not OMC.

    Any things I should be aware of?

    Any constuctive input?

    I don't need any one to tell me sell the boat or don't do it King Cobras are great.

    I love my boat and I want it repowered
    I hate my outdrive
    I hate my stock 454 600 hours
    I hate my spitfire ignition system
    I am tired of the shifting problems and repair costs

    Any info would be greatly helpful
    thanks guys

  2. #2
    Moderator Bondo's Avatar
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    Default Re: OMC king cobra package to mercruiser package

    I have heard that I may just need to drill some extra holes. is this true?
    Ayuh,....
    Will the inner gimble ring line up with the bell housing of the mercruiser once installed
    Ayuh,...
    Are the steering cables the same?
    Ayuh,.. Should Be...
    My shifter and throttle are offshore controls not OMC.
    Ayuh,... You might have to change the ends....
    Any things I should be aware of?

    Any constuctive input?
    Ayuh,...
    1 of the Regulars here has done pretty much the same Swap, with Great Results.....
    Just not the kind of HP #s you're lookin at....

    It'll almost be a Plug & Play refit......

    Good Luck,+ Welcome Aboard.....
    Any Grease is Better,..... Than No Grease at All.......

  3. #3
    Honorary Moderator Emeritus Don S's Avatar
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    Default Re: OMC king cobra package to mercruiser package

    Is the cut out in the transom for the King Cobra the same as the Mercruiser for bravo 1?
    Yes, the cutout is the same, there are 2 holes at the top of the transom shield not found on the Cobra. Not a problem to drill. The big problem with that setup will be the heigh of the hole. The X dimenstion is how hight the Center line of the crankshaft is. The higher HP race engines may be using a different height to make the drive work better
    Don S.


    Please, no PM's (Private Messages) regarding boat/engine problems.
    That is what the forums are for.
    Only forum/moderator issues will be answered in PM's.

  4. #4

    Default Re: OMC king cobra package to mercruiser package

    Sounds good so far, My doner boat belonged to a friend of mine and it came with a 7.4 and a bravo III. He changed the engine right out, with out any mods at all. If this is the case is the X dimention the same between Mercruiser and OMC 454/7.4

    after the swap he toasted his bravo III and justed bolted on a rebuilt outdrive. without any mods.

    any input on the X dimention

  5. #5
    Fleet Admiral HT32BSX115's Avatar
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    Default Re: OMC king cobra package to mercruiser package

    The King Cobra is GREAT , you should keep it! Especially if it's a 460 with Spitfire!!!


    Now having said all that!!

    I didn't measure the "X" dimension because the distance I measured from the Cobra Drive shaft to the propshaft was the same as the Bravo.

    The "X" dimension may be a factor, but to change it you'd have to patch the hole and re-cut it higher or lower possibly only a inch or two.
    (Now I'll probably go out there and measure it anyway...but there's still not much I can do about it.) The boat performs flawlessly! A little slower than the original 460/KC but Bravo III's are a little slower (3-5mph) but who cares?

    As far as the holes etc...yes they're the same. You may have to relocate the engine mounts a little forward or back depending on how it sits on the Merc mounts.

    I used the the whole Merc electrical harness. I bought a new Teleflex-Morse CH1700 control and new cables. I'm using the original steering wheel and cable that came with the boat. It's also Teleflex and it's universal.

    If you're going to put all sorts of HP and speed in that boat, you probably should be going to some type of high performance hydraulic steering system.

    Here's some pictures. If you look close you can see where the 'new" holes are (top) I made a little jig to drill them square with the transom.

    I also did a lot of drying out and fiberglass work in the whole engine compartment area. It wasn't sealed well from new.... I also did not use the thru-hull exhaust.(I had Capt's Call.... but no more) I rewired everything. It looked like a 5 year old kid wired the boat!



    Cobra


    Bravo







    Have fun!


    Rick
    73 de Rick
    ----------------------------------------------------------------------------------
    I use xxx oil and have never had a problem........
    1987 FourWinns 211 Liberator, 7.4L- Bravo III installed by ME,
    Formerly OMG 460 King Kobra powered
    1947 Stinson 108-2 Station Wagon
    , Franklin 6A-335B. Hartzell CS 2-blade prop
    -
    All PM's cheerfully answered! Please ask tech questions in the appropriate forum so everyone's included

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