318 head porting for the average joe

Small Block Mopar Engine

  1. dirty white boy

    dirty white boy 50 yr old Juvenal delinquent

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    what size valves you working with???
     
  2. MOPAROFFICIAL

    MOPAROFFICIAL FABO Gold Member FABO Gold Member

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    Atm, 1.78/1.50

    The exhaust valve in the pic is a stock 360 1.60 turned down to 1.50 for testing. The face is is wide enough to be cut and land right on the stock 1.50 seat in the head.

    I've done 1.88's too.
     
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    • fishmens67

      fishmens67 FABO Gold Member FABO Gold Member

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      :thumbsup: nice thread, great information.
      Did the original author die and become a legendary member ? lol
      I know he was at least 120 years old. Pretty smart old duffer.
       
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      • MOPAROFFICIAL

        MOPAROFFICIAL FABO Gold Member FABO Gold Member

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        I still get hbd's.. on not my birthday.
        121 now...:D..though after 20 years of laying carpet, playing drums in bands ,building motors, fixing my family's cars ..I feel about 121.5 yrs old
         
        Last edited: Sep 17, 2021
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        • MOPAROFFICIAL

          MOPAROFFICIAL FABO Gold Member FABO Gold Member

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          I started this thread, so I'm adding this 302 info to it, starting with this video.


          I will also post here pics and details how like this thread was orginally intended.
           
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          • Andrew vanman87

            Andrew vanman87 Member

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            What's the most cfm has anyone gotten from their stock 318 heads ( from porting ) and adding larger valves ? 260cfm possible ?
             
          • MOPAROFFICIAL

            MOPAROFFICIAL FABO Gold Member FABO Gold Member

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            Sure. But why?
             
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            • Jadaharabi

              Jadaharabi FABO Gold Member FABO Gold Member

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              .
              Pardon me while I whip this out.
              I think the question is what's the max you have gotten out of a pair of 318 heads?
               
            • MOPAROFFICIAL

              MOPAROFFICIAL FABO Gold Member FABO Gold Member

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              I have not max ported a 318 head with a 1.88. With a 1.78 valve they kind of stop in the 215-220 cfm range.
              I think 230-240cfm with a 1.88 is about it.
              I did some 'not all out' 1.88 273 heads and they went around 225 cfm. They end up near 140-145cc and that's tiny for anything but a 273/318. I don't think they would be the best choice for 6500+ rpm and or more cid..but it depends on the parts and pieces I'd suppose.
              You need so much volume to be able to 'refill' at that rpm
               
              Last edited: Oct 13, 2021
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              • dirty white boy

                dirty white boy 50 yr old Juvenal delinquent

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                go much farther youll hit water or itll be so thin itll crack....
                 
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