Engine Change Up!

Discussion in 'Powerboats' started by Irish McGee, Aug 19, 2013.

  1. Irish McGee
    Joined: Aug 2013
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    Location: Ozark Mountains

    Irish McGee Junior Member

    Hello Folks, I am new on this boat forum but I was wondering if anyone has information on the 6.2 stroker engines out on the market? My Sea Ray is in need of a set of fresh engines and I would like to lose those 4.3 twins she is carrying.
     
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I'll assume you mean a 383 CID small block Chevy. Typically these are regular 350 blocks, with a 400 crank, increasing the stroke to 3.75", which makes it a 383 with a .03" over bore, which is a safe "punch" for a stock 4 bolt block. Technically you can punch it out to .06" which will make here 388 CID.

    As to the suitability of these motors, well it all boils down the cam grind. The 262 CID engines you have now are limited in output, if only because of reciprocating mass. There's no substitute for displacement.

    Crate engines (350) will range in power, depending on many things. Both one and two piece rear main blocks, with 2 bolt mains will be in the 250 - 260 HP range. A 4 bolt, one piece rear main block (Vortec) will be about the same, though can tolerate considerably more, reliably, say 300 HP.

    I know of a few stroker crate marine engines, most in excess of 350 HP to 450 HP, but you'll pay dearly for these puppies. The same is true of the LS series.

    Lastly, how much are you willing to pay for a few more MPH? Most hulls have a sweet spot and it doesn't take all that much to get there (relatively), but the hull will also have a point of limited returns, whereas you toss another 150 HP at it, but only gain a single MPH or two. Simply put, what are you expecting from this upgrade? Also we'll need more information about your boat and it's current setup to offer and performance predictions.
     
  3. IMP-ish
    Joined: Jan 2011
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    Location: united states of america

    IMP-ish powerboater

    I'd like to know what drives you have?
    Not sure what came offered on your sea ray 290.
    The 4.3 and 5.7 less than 300 hp work fine with alphas. The higher hp fuel injected 350 and the strokers always come with bravos now.
    (There were exceptions --- I've been on a 1987 scarab panther that came with 454s and alpha drives (he had to rebuild his drives twice)
    And there were bajas done this way too in 1987/88. Some are still around. Too many snapped with more than a stock 350. Merc came out with the stronger bravo drive after that and now that's the only way to go for more hp.)
     
  4. Irish McGee
    Joined: Aug 2013
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    Location: Ozark Mountains

    Irish McGee Junior Member

    PAR I will say I know a whole lot more about golf clubs and the game, than I do boat hulls and the engineering that goes into them. I spent my younger years running around the Mid-West touring drag strips with my B-Gasser and GTO. Only Mickey Boy ever out ran that goat of mine and he had a ton of money and 18-wheeler backing him up with 4 engines inside. I was the country boy "shade tree" mechanic that kept most of those hot shots on their toes.

    Now back to this boat of mine, I thought of putting 2 engines together my self, as I just don't trust these so called engine builders and crap that comes from other places than the USA. I have 2 of the 400 cu in truck engines just sitting in the barn right now. They been there for 15 years or so I guess. I know that make darn good race engines but I am not into the RACE thing anymore. I just would like this boat to do around 50 miles per hour. However it that is not possible without puttong one of my Uncle Zinc's Turbo's in the the boat than I guess my exspectations will have to be shortened a bit. I don't believe I have the room for the 7.4's engines and besides they weigh a bunch.
     
  5. Irish McGee
    Joined: Aug 2013
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    Location: Ozark Mountains

    Irish McGee Junior Member

    Impish this boat of mine came with a pair of V-6's!
     
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    You should also take into account that you will have to re-gear and re-prop, which will add to your expense.
     

  7. Irish McGee
    Joined: Aug 2013
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    Location: Ozark Mountains

    Irish McGee Junior Member

    Gonzo I realize that fact! Yeah nothing like spending money for new outdrives, most likely Bravo 2.
     
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