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Thread: Old original engine, Rebuild or Retire...

  1. #1
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    Old original engine, Rebuild or Retire...

    I purchased a Donzi Hornet 2, 1977. It was 5+years sitting in a field in California Gold country. It is now my new project (psycho therapy). It is mostly original. The engine is a 350 FLV, produced by Chris Craft for their sport boat line. It's listed as having 300 hp.
    Question...should I have this unit rebuilt, or replaced with a crate engine with modern parts and a lot more power.
    I would like to dress it up to look like the original.
    I plan to restore and reuse the Hardin exhaust (80's aftermarket).

    Still looking for a restoration tread.
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  2. #2
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    You should have put this under the performance talk section for max coverage .
    But from recent personal experience I can tell you that there's a massive difference between the output of that engine compared to today's version with the same cubes.
    Your helm is also portside which means that if you go with a complete re-power package you'll have to get a unit with counter rotation but you may be considering retaining the Volvo unit . Is it in good enough shape to handle the boost in power ? And if it's not a trimable unit that's something you're going to miss.
    You have a lot of work ahead of you for sure but they're great riding hulls . Job #1 , get that fuel tank out !
    Just because something's old doesn't mean you throw it away !

  3. #3
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    I?d suggest at new 350 crate engine

    A brand new 325hp 350 cube marine base engine with vortec heads is about $3500. Another $2000 for everything new minus the exhaust. The vortec 350 can be easily bumped to 400hp with a cam change if desired. This is the route I chose with my 1994 18c.
    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

  4. #4
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    Quote Originally Posted by Pat McPherson View Post
    A brand new 325hp 350 cube marine base engine with vortec heads is about $3500. Another $2000 for everything new minus the exhaust. The vortec 350 can be easily bumped to 400hp with a cam change if desired. This is the route I chose with my 1994 18c.
    I agree with both comments above. I'd drop in a new 350 as Pat suggests. But also consider your outdrive and what your options are. If you need to replace the core in the transom you can make the cutout for whatever drive you want, but you need the counter rotation as mentioned above. It's doable and I'd go that route especially if the current drive doesn't have trim.

    '07 22 Classic Shelby GT
    '96 18 Classic - sold
    '69 16 Ski & Sport - sold


  5. #5
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    1996-present 350 mag

    $3450 for base engine and $350 for marine intake. Same engine used by Merc for 350Mag rated 300hp at the prop.
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    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

  6. #6
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    Easy to spend others $

    The old Volvo 280 shifting is as smooth as silk but parts are hard to come by.
    I believe there are adapter plates to convert the large transom cutout for newer Volvo or Merc drives.
    Personally I?d have the transom redone and install a Merc Bravo. LH or RH rotation is just a linkage swap for a Bravo and good for 500hp.
    Thank you, Patrick
    1994 18' Classic 350Mag Alpha

    Previously owned Donzis -
    1996 22' Classic, 502Mag Bravo
    1987 20' Minx, 350Mag Alpha
    1975 18' Classic, 350Chevy Volvo 280

  7. #7
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    Wow. Thanks for the Input

    The original 280 outdrive is trashed with parts missing. I plan to replace it with a new unit. I don't trust a rebuilt 280 could handle much more than the original 300 horsepower. I was looking at West Coast Engines, specifying the Edelbrock marine intake and a Sierra water pump. I can clean up the old exhaust. How do you guys feel about the new Holley and Edelbrock EFI units now available.
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  8. #8
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    Quote Originally Posted by DeltaDonziHornet2 View Post
    The original 280 outdrive is trashed with parts missing. I plan to replace it with a new unit. I don't trust a rebuilt 280 could handle much more than the original 300 horsepower. I was looking at West Coast Engines, specifying the Edelbrock marine intake and a Sierra water pump. I can clean up the old exhaust. How do you guys feel about the new Holley and Edelbrock EFI units now available.
    The Volvo 280 drive can be built to handle 500 HP. Stock it can handle 325 When I restored my Magnum 27, documented here on "talk about other boats" I had each drive built for a specific direction of rotation. Prior to proceeding down this path I spoke with numerous old school racers and marine mechanics, they all agreed that the 280 is a super strong drive. The weak link with the Volvo drive set up came with the speedmaster lower unit which did not have an adequaete fluid reservoir.

    My recommendation, use only a 100% synthetic gear oil. I use Redline shockproof:
    https://www.redlineoil.com/heavy-shockproof


    Transom condition will dictate your direction, and when an old boat is this far apart you'd be wise to rebuild replace the wood core of the transom.

    Mario L.

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