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Thread: donzi blackhawk with a weiand super charger 502

  1. #16
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    Some pics

    A couple more pics
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  2. #17
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    She looks absolutely beautiful!!!...........Good luck and enjoy!!
    1983 Cigarette 35' Mistress
    1976 Magnum 27' Sport
    1986 Donzi 18' Classic
    NEVER FORGET 9/11

  3. #18
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    Ok I found a Blackhawk drive at a price I may be willing to pay (still have to find props though). I need some expert feedback here. From reading a bunch of internet posts it appears that the blackhawk outdrive was only offered on the 502efi as the efi allowed the motor to be idled slow enough around the dock and shifted(?). Some people mentioned breaking the drive if it is shifted while the motor idles to high.

    If you just began reading here, the motor in my boat is a blown carburated 502 making (from what I am told and no reason to doubt) about 550hp. Am I able to run this outdrive without making modifications to the engine as it sits now without risking hurting a blackhawk drive? If someone can explain this a bit better I would very much appreciate it.

  4. #19
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    Im not an expert, but...

    There are lots of boat running Blackhawk drives with more power than the 415HP/502MPI.
    My bett is that many of the gear and shaft upgrades that are done to standard B1 drives can and are done to the Blackhawk drive.
    I know there was a fellow posting here that had a 22' Classic with high output 540cube running a Blackhawk.
    Ever post on Off shore only? there is a drives area of that forum...
    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

  5. #20
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    From what I have read the blackhawk drive is good for up to 600hp. I was looking for more info on the efi only stuff I read and dont fully underatand. If I understand it rifht the blackhawk needs a low rpm to shift amd be manageable around the dock and this is not as do-able with a carb engine. Just trying to get educated here, hoping someone can clarify. You can't believe everything on the interweb.

    I have been reading everything I can find, including offshore only, but never posted there.

  6. #21
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    Same as or similar to Bravo 3

    The Blackhawk shares many of the same components with the Bravo 3.
    My bet is that high rpm shifting can more easily damage the clutches and gears. You've got more inertia/load with having two props and 2 drive shafts.
    It may also be that an efi engine can be programmed to cut spark/power while shifting similar to the cutout switch used on Alpha drives.
    You will have less prop slip in the water with 6 blades and counter rotation so the boat is going to move quickly thru the water at idle even at low rpm.
    The OEM has to be conservative when warrantying a product. What does your engine idle at?
    I've been told that a Bravo should be shifted under 1000rpm so you're probably fine under 800 with a Blackhawk.
    Keep researching, there are guys that have much more radical engines running blackhawks for sure...
    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. #22
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    Quote Originally Posted by Pat McPherson View Post
    Keep researching, there are guys that have much more radical engines running blackhawks for sure...
    Had the same thought...for one I thought some of the Lip-Ship Cig 20s had big power with BH drives.
    "I don't have time to get into it, but he went through a lot." -Pulp Fiction

  8. #23
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    Appreciate the advice!

  9. #24
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    20' Cig with big power

    Quote Originally Posted by Ghost View Post
    Had the same thought...for one I thought some of the Lip-Ship Cig 20s had big power with BH drives.
    Yes, there is a 20' Cig with big power and Blackhawk running over 100mph.
    The fellow MDonziM that had the 22' Donzi and 540 hook to Blackhawk is building that Midnight express he shared here. Ask him about the Blackhawk.
    http://www.donzi.net/forums/showthre...ess-32-Project
    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

  10. #25
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    Quote Originally Posted by ClintB View Post
    Ok I found a Blackhawk drive at a price I may be willing to pay (still have to find props though). I need some expert feedback here. From reading a bunch of internet posts it appears that the blackhawk outdrive was only offered on the 502efi as the efi allowed the motor to be idled slow enough around the dock and shifted(?). Some people mentioned breaking the drive if it is shifted while the motor idles to high.
    I caution you about getting a BH if you don't have props. You'll need the 31's with your motor and those are the hardest ones to get. I've only seen a 2 sets come up for sale in the last few years and they went quick. Granted I wasn't looking hard for a set, but I do casually look around.


    Quote Originally Posted by ClintB View Post
    From what I have read the blackhawk drive is good for up to 600hp. I was looking for more info on the efi only stuff I read and dont fully underatand. If I understand it rifht the blackhawk needs a low rpm to shift amd be manageable around the dock and this is not as do-able with a carb engine. Just trying to get educated here, hoping someone can clarify. You can't believe everything on the interweb.

    I have been reading everything I can find, including offshore only, but never posted there.
    As far as I know, the 502efi was set up with a lower idle to accommodate the BH. It wasn't the only motor to get the BH though. The Scarab P29 used twin small blocks with the BH. I don't know about breaking shafts, just by shifting into gear. IMO, if that happened, the shaft was about ready to let go regardless. You do want the idle as low as possible though, because it does shift hard, and twin 31's push the boat pretty briskly even at 6~700rpm

    The BH can take as much hp as a standard Bravo. What that amount is has been open for debate for years. Merc certainly does not rate the BH to 600hp......but there are plenty of drives running at that hp. The upper is Bravo 1 and the lower is Bravo 3. The only parts no longer available are the vertical shaft and the case.

    IMHO.........and this is only an opinion......if your boat runs good with the current drive, I'd leave it as is.......unless you find a good deal on a BH with props, so if you don't like it, you can always sell it for what you paid.
    Why is faster never fast enough.

  11. #26
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    Clintb,

    I sold my 22 last year. It was originally a standard bravo set up with a 502. I put a 540ci/ 650hp motor in and ran a BH drive on it.
    Feel free to call me regarding any issues you may have.
    Marshall
    5162866131
    1978 Magnum Starfire "MAYHEM"
    1994 Donzi 22 Classic 540/Blackhawk - Sold
    1982 Midnight Express 32 SS

  12. #27
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    one thing you could do if you are concerened about shifting at higher RPM or really with too much torque is install a shift interrupter that drops a couple cylinders and uloads the drive.

    There are a few aftermarket ones out there, I bought one from CDI that was designed to work with HEI type distributor.
    Jay Z.
    '93 White/Teal Classic 22

  13. #28
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    That boat look awsome,,, the gold hardware really stands out
    sweet ride!!!
    FISH HARD

  14. #29
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    Quote Originally Posted by yeller View Post
    ...



    The BH can take as much hp as a standard Bravo. What that amount is has been open for debate for years. Merc certainly does not rate the BH to 600hp......but there are plenty of drives running at that hp. The upper is Bravo 1 and the lower is Bravo 3. The only parts no longer available are the vertical shaft and the case.

    IMHO.........and this is only an opinion......if your boat runs good with the current drive, I'd leave it as is.......unless you find a good deal on a BH with props, so if you don't like it, you can always sell it for what you paid.
    The xr gear set is available for it. Merc will pair the 520 with the bravo 3 xr and will pair the bravo1 xr with the 600 from the factory.

    I remember reading a few years back that a company would cnc BH props and I heard a rumor that the company that originally made the props still had the molds and was considering a run of props. Can't remember what the company was though. The cnc wheels were cost prohibitive so the latter would be more ideal

  15. #30
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    Quote Originally Posted by VetteLT193 View Post
    I remember reading a few years back that a company would cnc BH props and I heard a rumor that the company that originally made the props still had the molds and was considering a run of props. Can't remember what the company was though. The cnc wheels were cost prohibitive so the latter would be more ideal
    Yes, I remember reading that also. I believe Hoss Props will make BH props. It was well over $5k, and that was a few years ago.
    Why is faster never fast enough.

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