Small block camshaft

Discussion in 'Sterndrives' started by tuantom, Apr 18, 2007.

  1. tuantom
    Joined: Jan 2005
    Posts: 182
    Likes: 3, Points: 18, Legacy Rep: 45
    Location: Chicago

    tuantom Senior Member

    How big can you really go before reversion becomes an issue?

    I read Beech2000's post stating that his guys said his cam had too much overlap and would be problematic - I think it was @ .050" in/ex 218/224 112 LSA. I just installed a bit smaller cam - 212/218 112 LSA - but one that is close enough to his to raise an eyebrow.

    What other factors contribute to - and by how much - exhaust reversion. Are some manifolds better than others? Height above water-line? Thru-hull vs thru drive?

    I'm currently running the old Mercruiser style logs, a volvo drive, and thru-hull trumpets; but they are from the late 70's and probably approaching their end, so I am contemplating a change to center rise manifolds. Would this contribute to or reduce the possibility of reversion. After spending so much time and money on my engine, I'd hate to introduce a major flaw. A couple more ponies isn't worth it.

    Thanks
     
    tuantom, Apr 18, 2007
    #1
  2. stonebreaker
    Joined: May 2006
    Posts: 438
    Likes: 11, Points: 0, Legacy Rep: 42
    Location: Shiloh, IL

    stonebreaker Senior Member

    Your cam will probably be fine. GM's stock marine cam is close to yours - 214/222 duration and 112 LSA. I've run that exact GM cam in my car, and it idles just fine - it even passed a tailpipe sniff test. Idle was fine, too - most people couldn't even tell a difference from stock.
     
    stonebreaker, Apr 22, 2007
    #2
  3. jimslade
    Joined: Aug 2005
    Posts: 304
    Likes: 3, Points: 0, Legacy Rep: 27
    Location: north Markham

    jimslade Senior Member

    Stay under 220 and you will be fine.
     
    jimslade, May 10, 2007
    #3

  5. tuantom
    Joined: Jan 2005
    Posts: 182
    Likes: 3, Points: 18, Legacy Rep: 45
    Location: Chicago

    tuantom Senior Member

    Thanks

    Good news. Thanks for the replies
     
    tuantom, May 11, 2007
    #4
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