'308' vs 1976 360 heads

Small Block Mopar Engine

  1. pishta

    pishta I know I'm right....

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    What the diff when porting? 308 has porting template but it says it wont work on any other head besides the 3 MP heads and the 308. I know the AIR ports are cast but....? Would templates get you close with obvious to see obstacles of 1976 era head?
     
  2. Ottmundr

    Ottmundr 68 Fastback

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    Hey Pishta, do you have a part number handy for the porting template?
     
  3. pishta

    pishta I know I'm right....

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    • 273

      273 Well-Known Member

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      I’ve always heard the 308 had a better exhaust side, don’t know if that mean intake is similar
       
    • PRH

      PRH Well-Known Member

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      Of the stock 1.88 heads I’ve tested, the higher lift(from .400 and up) intake flow was better on the 308’s than others.
      Not way better, but better.

      The exhaust is okay ootb, but where the ex port shines is how much better it is with some porting, because of the filled in floor.

      On the right type of build, they would be a pretty easy 400hp head(with some mild reworking) on a hot 360.
      But...... if you’re paying to have it done...... they’d cost you more than some new SM aluminum heads.
       
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      • pishta

        pishta I know I'm right....

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        For your viewing pleasure....
        360ports.jpg
         
      • pishta

        pishta I know I'm right....

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        @PRH mark up the areas that can be helped if possible.
         
      • PRH

        PRH Well-Known Member

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        That pic is a bit too generic to accurately point to anything specific.

        For mild reworking, you wouldn’t approach them any differently(well.....”I” wouldn’t) than a set of J heads.
        Cut the seats, bowl cut, blend that into the runners, trim/bullet nose the guide boss.
        One key area on all of those SB heads is the SSR, and the correct form for that can’t be seen by looking in from the bowl or gasket side.
        I do it by feel.
        Laying it back helps with higher lift flow when done properly.

        There is water under the SSR, so the more you rework that area, the more likely you are to find water.
         
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        • MOPAROFFICIAL

          MOPAROFFICIAL FABO Gold Member FABO Gold Member

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          Close enough. Maybe the water jackets were revised? Probably why they cracked more often. Air speed diff at the pinch. Obviously.lol
           
        • brian6pac

          brian6pac Well-Known Member

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          That is why I got a ultrasonic thickness tester, for porting heads.
           
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          • brian6pac

            brian6pac Well-Known Member

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          • pishta

            pishta I know I'm right....

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            308 years I guess. I don't think they have porting templates for the LA heads...only 308 style "swirl port" unless someone else seen 'em for LA older 360 heads or knows if they work with older heads. I think its a 'style' thing, not one port job will be ideal and every porter will critique any other porters work.
             
          • PRH

            PRH Well-Known Member

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            :soapbox:
             
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            • MOPAROFFICIAL

              MOPAROFFICIAL FABO Gold Member FABO Gold Member

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              Approach, mainly.
              If some...would offer a thumbs up once in a while..they might not come off like an ass..instead they post charts and basically self advertise. Usage of '?' is a courtesy as well. Lmao Some aren't self aware in a health way, and go on autopilot.
              Its get lost in keyboard space.
               
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