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  1. #1
    Registered Pure Energy's Avatar
    My Boats:
    2001 Superboat Y2K
    Join Date
    Oct 2000
    N. NJ, Eastern LI

    Question Installing new 502 short blocks, what to do to get more power?

    During a water test mechanic damaged both engines. Owner is going above and beyond what could possibly be expected and is going to replace both engines with shortblocks. While engines are apart what could be done to increase HP. Motors are supercharged. Blue printing, cam, head work etc. Willing to spend about 3 g's.


  2. #2
    My Boats:
    1997 23' WPM Cat!!
    Join Date
    Feb 2002
    LaPorte IN.
    What heads are you using? If you are using stock rect. port heads have them pocket ported, install 2.25" intake valves, and have the combustion chambers polished. I would set up the heads for a hydraulic roller cam and talk to one of the engine builders that post on the board about which grind to use. I would then go with a Merlin single plane intake and Holley 830 carbs. That combo should be worth close to 500 hp. Voodoo just posted some dyno numbers on his enhanced 502. I think you will be in the same ballpark with the parts I mentioned and if you already have the heads 3g is close to where you'll be. Good luck.

  3. #3
    My Boats:
    2003 Single 32 Dominator
    Join Date
    Oct 2000
    claymont, DE, USA

    In my opinion, with only 3K to spend, and two engines to divide amoung, best money is spent on head work. Without a doubt.

    You could spend that much in head work, easily, between two sets of heads.
    If you don't spend quite that much, a hyd roller cam is always a good investment for a boat staying under 6000 r's.
    For a supercharged 502 (gen 6), my opinion is the Crane 168741. It's a 236/244 112 .610/.632

    Even if you do spend 3k on your heads, as long as you're set up for a hyd roller already, it would only cost an extra ~$600 to put the 2 new cams in.
    That cam lists for $266 in Jegs.

    Another huge thing is quench space. With head gasket included quench space, (the space between the flat part of the piston and the flat part of the head at TDC) should be min of .040 and max of .060.

    There, see how fast 3k can go???


  4. #4
    Platinum Member Platinum Member
    My Boats:
    fuel injection, superchargers
    Join Date
    Jan 2001
    PA and MD

  5. #5
    That 168741 is 320.99 from Jegs and good luck finding the Crane Hyd. roller lifters to fit GenVI, the 16535-16 is the # I think. I got my cam from Jegs they didn't have the lifters in stock at that time though, I got them from Scoggins-Dickey,last set they had($390 to the door). If you do different heads you may need longer pushrods, I did($190) and still waiting for them. If you don't go with new heads you will need new valve springs for the .632 lift($150). Hydraulic roller stuff is cool, but expensive. Good Luck Jay

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