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  1. #1
    My Boats:
    1999 Cobalt 293 and 1974 Cigarette 20
    Join Date
    Aug 2001

    GM 502/502 Engines

    I'm going to look at a 1985 Wellcraft Excalibur Hawk with new GM 502 crate engines installed (10 hours). I've heard before that certain mods should be done to "marinize" them. If so, what are they?

    Do these engines make good boat motors?

    The boat's a good candidate for a minor, cosmetics-only project. Likely needs interior, paint, guages, etc... I don't want to get into realiabilty issues in the engine/drive department. Boat has TRS drives and Borg-Warner transmissions.

    Any known issues/problems with the Excaliburs besides the massive weight? Hull, stringers, transom, etc...

  2. #2
    my last boat had 502 crate motors.
    both had to have head gaskets replaced.

  3. #3
    Platinum Member Platinum Member mcollinstn's Avatar
    My Boats:
    1991 F311SR1
    Join Date
    Sep 2001
    Do you know that they are the ZZ502/502hp flavor?

    If so, be advised that the aluminum heads do not care for salt usage. The intake manifold is not bronze lined for salt duty. The cam is prone to reversion depending on what exhaust system and riser height you are using. The head gaskets are not salt rated. Needs brass freeze plugs. I'm sure I'm leaving something out....

    The 450 hp crate 502 has the freeze plug, head gasket, and intake manifold issues.
    I see London, I see France...

  4. #4
    My Boats:
    1999 Cobalt 293 and 1974 Cigarette 20
    Join Date
    Aug 2001
    Never mind.... saw the boat yesterday. Not worth the effort. Boat was totally neglected and in bad shape.

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