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  1. #1

    Default GM 3.0 to stright marine drive

    Have a small plywood inboard (Correct Craft, Atom Skier) powered by a Gray marine 70 hp flathead 4, would like to increase power without butchering the hull. Was thinking a 3.0 Gm based 4 cylinder of 120-140 hp would give me a nice power increase. I know theses engines are used in many IO applications but was wondering if they can be adopted to straight inboard drive using a velvet drive or whatever.

    Any thoughts or opinions, using other choices,would be appreciated. Thanks in advance

  2. #2
    Join Date
    Sep 2008
    Location
    Maryland - USA
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    6,755

    Default Re: GM 3.0 to stright marine drive

    should work...assuming you have enough space....

    Just make sure the shaft and strut are adequately sized and are in good condition....figure a new prop (or repitch, if you are lucky) as well....I'd also change the bearing and stuffing box hoses, as applicable, while its apart.

  3. #3

    Default Re: GM 3.0 to stright marine drive

    Not sure what I need to connect engine to a velvet drive trans. Does the 3.0 share the same bellhousing as, say, a chev v8?

  4. #4
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    6,755

    Default Re: GM 3.0 to stright marine drive

    pretty sure they all have the same bolt pattern - block to bell housing....

    you'll need a solid flywheel and a damper plate to bolt to it, with the splines to match the velvet drive's input shaft.

  5. #5
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,142

    Default Re: GM 3.0 to stright marine drive

    Quote Originally Posted by makomark View Post
    pretty sure they all have the same bolt pattern - block to bell housing....

    you'll need a solid flywheel and a damper plate to bolt to it, with the splines to match the velvet drive's input shaft.
    Ayuh,.... Block to flywheel cover bolt pattern is the same, I-4 to I-6 to SBC to BBC,....

    Crankshaft bolt patterns, 'n flywheel balance does change is some instances,...
    Any Grease is Better,... Than No grease at All....

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