Compression Ratio?

Discussion in 'Engine Topic' started by 71RS350, Apr 19, 2009.

  1. 71RS350

    71RS350 Moderator Gold Member

    3,434
    0
    May 10, 2004
    Mooresville,NC
    hey guys...thinking about switching out my heads with aluminum 64 cc heads...currently runnin factory 76cc heads on flatop pistons and .040 overbore....would be around 10:5?....
     
  2. hhott71

    hhott71 Veteran Member Lifetime Gold Member

    14,373
    0
    Mar 30, 2001
    Joplin Mo. 64801
    Flat top 350
    general average:
    76cc heads = 9:1
    64cc heads = 10:1

    64cc heads and a 0.100" dome piston = 11:1
    64cc heads and a .250" dome piston = 12:1

    Depending on valve reliefs, gasket thickness, deck height those general numbers can vary about .25 of a point.

    But the numbers are close enough for the information given in your post.
     

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