SpeedMaster Heads for a 5.9 Magnum

Small Block Mopar Engine

  1. DodgeFan79

    DodgeFan79 Member

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    Does Speed Master make heads for the Magnum motors? I’m looking on there web site so I may find them. Do they come with upgraded valve springs? What are some opinions on them? Looking to put a set on a stock short block and install bigger cam and there intake. Thanks
     
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    • Garrett Ellison

      Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

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      @MOPAROFFICIAL
      has worked with these heads some.
      It looks like the Black Friday promotion may be back on the CNC heads.
       
    • DodgeFan79

      DodgeFan79 Member

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      Is there a certain head I should choose? Can I run the stock rocker setup?
       
    • rumblefish360

      rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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      Information on there site has proven to be inaccurate.
      There aluminum head appears to be the basic Edelbrock rip off. They do advertise a iron Magnum head.


      The head you choose? Depends on what your going to do with it. Are you oiling via the pushrods?
      What rocker set up?
       
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      • DodgeFan79

        DodgeFan79 Member

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        I would basically be running a stock 5.9 Mag with a cam upgrade and convert to carb. So stock valve train.
         
      • rumblefish360

        rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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        Iron head then?
        The OEM rockers are fine.
        What cam are you considering?

        I also run a stock ‘00 - 5.9 long block w/bolt on parts, no cam yet. I outfitted the long block with a small Edelbrock 600, rpm intake, 1-3/4 headers into a 2-1/2 exhaust, junk yard distributor w/a chrome box ignition. 727/3.55’s. It’s very good for what it is.
         
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        • DodgeFan79

          DodgeFan79 Member

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          The iron heads SpeedMaster has are bare. Was wanting to get a set ready to go I know they would need checked. Could I run the aluminum heads on a setup like this? Would I have to use a different rocker set up?
           
        • rumblefish360

          rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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          IIRC, the aluminum heads are designed for the LA, which means you have to figure out how to oil the valve train. The Magnum engine doesn’t have provisions for this.

          Yes, you’ll need an LA set up, rockers that can be oil feed through the pushrod. Comp Cams has a set that’s able to be pushrod oil feed for the LA engine as well as LDQ / PDQ or something like that I think the companies name is. I forget, I’m sorry.

          Check summit racing for the Comp rockers. There only available in a 1.5 ratio, none in a 1.6 ratio.
           
        • 66fyssh

          66fyssh Don't Stop Believin' FABO Gold Member

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          I went on their website, selected Cylinder Heads, then Chrysler. The first Alloy head on the left is Big Block. The one on the right states 318-360, but when you read the description it sounds like a Magnum head. It's oil through pushrod design. But it doesn't come with guide plates so I dunno. Poor info.
           
        • rumblefish360

          rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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          When moparoffical gets here, he’s going to rip those heads a new A-hole like he’s in rush to do so before the ICBM lands on his head.

          The heads port out well, but as fast, OOTB…..
          Ehhhhh, not so good.
           
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          • rumblefish360

            rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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            Poor I for all over.
            Wait until MPoffical gets here!
             
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            • 66fyssh

              66fyssh Don't Stop Believin' FABO Gold Member

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              Pittsburgh Racer had good luck with them.

              I don't have a dog in the fight, I went with Edelbrock on my build.
               
            • rumblefish360

              rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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              Pittsburgh racer ported his. The OOTB condition is what MPoffical will attest to. Not the ported and finished product.

              @pittsburghracer
               
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              • MOPAROFFICIAL

                MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                They are 1.92/1.62
                150cc intake port
                60cc exhaust port
                The stem size is 8mm, stock magnum.
                They peak 245 cfm, but the low lift numbers are horrible, garbage.
                You cannot run this head ootb.

                It needs some deshrouding ,stones, hand blending. Itll do great after that.
                If you use use 1.94/1.60 11/32 valves, yes you can cut 1.60 from 1.62, itll do about 260cfm intake and 212cfm exhaust with the right blend port work. Exhaust work is minuscule with a radius seat job.
                62 cc chamber ootb iirr.
                Stock chevy length is about a drop in with stock rockers in a magnum. The +.100 stems @5.025/5.011 will yield a spring height of around 1.725 . If going the +.100 route and using stock pushrods, geometry aside, will require a 5/16 .065 thick hard washer under the rockers pedestal bolts if a magnum short block is being used.
                I'll be posting some numbers for 2.02 versions I've been working on for a memeber here soon.

                Speedmaster lies, so dont believe the site info on them. They are not 179cc.
                If they were...you would be able to read many threads on them because there is a market for an iron magnum head with the loss of rhs/eq. They are somewhere in the 'like a eq' bracket so far..
                 
              • 66fyssh

                66fyssh Don't Stop Believin' FABO Gold Member

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                What was it he measured...runner volume...and it was way off??
                 
              • rumblefish360

                rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                I’ll let MPO (reply above) do the talking.
                 
              • MOPAROFFICIAL

                MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                The speed master aluminum head just needs a good valve job ..though could benefit from a 2.05 or bigger intake valve to gain a better venturi bowl shape. Exh port work required is minimal.
                I'd do a little chamber shaping at the far side and light short turn chamber side pathing is all.

                20211110_184656.jpg
                 
                Last edited: Nov 25, 2021
              • DodgeFan79

                DodgeFan79 Member

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                Looks like I may be better off just getting a set of remanufactured heads or new heads if I can find them that are iron and upgrading the valve springs so I can run a bigger cam. The build nots gonna be radical.
                 
              • DodgeFan79

                DodgeFan79 Member

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                Looks like if I run the aluminum heads I can’t run the stock valve train set up???
                 
              • MOPAROFFICIAL

                MOPAROFFICIAL FABO Gold Member FABO Gold Member

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                If you know a shop that knows performance work... they can do a valve job and set them up for you. If you're near California.. I can do it... Like I said, they're a good head once you do the work...even in 1.92/1.94 form... they make great power.. just not ootb. I'll tell you this... you'll be wasting you time and money buying a factory casting stock head.
                I a set of them on my truck, 1500 4x4 camper shell big tire stockish 3" lift 300k mile bottom end with built transmission... its better than new ever was, flat out hauls ass.
                 
              • rumblefish360

                rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                Yes and no. More flow, more power. More flow isn’t limited to the high lift nor is it limited to the top end rpm or speed factors. A good valve job, minor bowl work is what MPO shows and it improves the low lift and low to mid rpm range really well. IMO, with the Black Friday sale going on, (and if I were in your shoes) I’d get a pair and send them out to be worked on. MPO could easily do the work for you or if your more comfortable with a local guy, that’s fine as well.

                MPO has been fooling around with these for a while.

                These heads will out flow the iron heads IIRC, stock OOTB or worked on equally. So, I’d run the better head. All ways purchase the best head possible! It’s the best power return you’ll get. Mild or wild.

                That’s correct. When you look at your cam, one with the most lift to work with your heads is what you’ll be looking at. A quick valve lifting cam is what you seek. The rocker ratio won’t matter. Just the net lift.

                The Comp rockers are an additional cost, but worth it in terms of an accurate ratio and strong rocker.

                Also by running the aluminum heads, there an LA intake manifold pattern which opens up choices and used ones are all least cheaper.
                 
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