Intake manifold fitment

Small Block Mopar Engine

  1. JjyKs

    JjyKs Member

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    So, I just purchased my first mopar with small block 408 stroker a while ago, and have been thinking about EFI conversion. Currently it has 2x 450 Holleys on top of a tunnel ram connected to some Edelbrock heads.

    I know that there's a Sniper EFI kit with dual throttle bodies, but that seems like a bit of overkill since even the single body version should be ok for 650hp (this car has been dynoed for 360hp on the wheels).

    So, as a Mopar newbie: How can I know which intake manifolds fit what? Is it enough to know that it's a small block (I actually don't know what size it was before the stroking) or should the manifold be matched to the heads?

    965a812abec4f0a6931d46b4bfacebfc (1).jpg
     
  2. Phreakish

    Phreakish Well-Known Member

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    Intake should match heads. A short list of heads includes Magnum, LA, W2, and plethora of factory and aftermarket race stuff.

    Most people with w2 stuff know they have it, it's pretty special stuff. Magnum vs LA is easy to tell - Magnum has vertical intake bolts.

    The biggest factor tends to be in the rockers and whether they're offset or not. Most aren't. There are also multiple offsets.
     
  3. ocdart

    ocdart Inland Mopars Car Club FABO Gold Member

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    The pic of your engine shows it has 'LA' valve covers since each valve cover has 5 bolts. Magnum engine valve covers have 10 bolts.
    But that isn't decisive since you can use 'LA' valve covers on Magnum heads by only utilizing 5 bolts.
    The common way to build a 408 stroker is to start with a 360 - either a 'LA' 360 or the later Magnum 360. You will need to dig inside to find out what it is.
    If you are considering a change from carbs to EFI, you should also determine your existing cam specs. EFI is happier with fairly mild cams.
     
  4. lilfontleroy

    lilfontleroy annoyinglilLeroy FABO Gold Member

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    • Locomotion

      Locomotion Well-Known Member

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      One thing related to all builds & brands, even with the "correct" manifold, is that you can't be sure if the next manifold you get will "fit" due to block decking, head milling or intake milling. Sometimes you'll see the intake bolt holes ovaled-out to get the intake bolts to line up with the heads. But doing that does not line up the ports! The results are mismatched ports and performance not meeting full potential.

      For starters, you can lay the new intake on the long block without a gasket and see if the bolt holes line up. If they line up well, it means that you'll have to mill the intake or the intake side of the heads the thickness of the compressed thickness of the gasket to be used so it does line up in final assembly. (Using supplied end rail gaskets complicates things because they can hold the intake up. I usually use silicone there for final assembly.)
       
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      • diymirage

        diymirage HP@idle > hondaHP@redline

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        • 67Dart273

          67Dart273 FABO Gold Member FABO Gold Member

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          I guess the current state of Pro Stock/ NASCAR must run some pretty mild cams LOLOL
           
        • JjyKs

          JjyKs Member

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          Yea got in contact with the last owner and it definitely is 360 small block.

          That actually looks good. The overkill part of my thinking was that dropping +2k€ on the EFI is too much if even the single body version that costs ~1k€ is enough. I have no idea how much people would actually pay for my old tunnel ram + carbs, but thought that it might be a lot cheaper with same power outcome to just sell my old parts and get new intake manifold and single quad EFI.
           
        • diymirage

          diymirage HP@idle > hondaHP@redline

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          ok, so you want to go EFI, but the main thing is the cost of the second body, compared to a single one

          well, first things first, if you dont swap the intake, you will not recoup any money, so you need to pay for both the EFI bodies, and the pump, but nothing else


          if you get a single 4 barrel intake you need to buy a new manifold, some gaskets, one throttle body and a fuel pump

          that is, if everything goes well

          as locomotion mentioned, there is a chance the engine block has been decked so far the intake manifold had to be modded to fit
          IF this is the case, you would need to include machine cost on the new intake aswell


          as far as resale value, i have no idea what those go for in Finland
          i can imagine the resale being higher because there are so few of them there...but that could also mean it will be hard to find a buyer
           
        • oldkimmer

          oldkimmer FABO Gold Member FABO Gold Member

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          The fitech is areal nice system either 2x4 or single 4. U won’t be disappointed. Kim
           
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