Slant 6 to V8 cooling

Heating / Cooling / AC

  1. John Cailey

    John Cailey Crizila FABO Gold Member

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    Transplanting a 318 Magnum motor where a /6 used to live. Core support opening is too small for a V8 radiator. Any suggestions would be appreciated - before I start cutting. Thanks, John
     
  2. Murray

    Murray FABO Gold Member FABO Gold Member

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    What car? A V8 radiator should bolt in- up to a BB/hemi radiator. No cutting.
     
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    • John Cailey

      John Cailey Crizila FABO Gold Member

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      74 Duster - original /6 car. Just read another thread on this subject. I have a new stock V8 A/C rad that looks like it is gonna sit too high unless I do some bottom core support cutting. Will also have to drill some new mounting bolt holes ( wider ). /6 core support opening ( width) is also a few inches short on both sides. I guess I just gotta start chopping away. UGH!!
       
    • hoosierdaddy

      hoosierdaddy FABO Gold Member FABO Gold Member

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      I just swapped a /6 for a magnum and just bolted in my new radiator with no problems . I did have to drill a couple of mounting holes ? What are your radiator dimensions ?
       
    • Demonic

      Demonic Well-Known Member

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      I've never had to cut the bottom of the core support. A 74 Duster should have at least a 22" opening, plenty for a hot 340.
       
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      • roccodart440

        roccodart440 Well-Known Member

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        You sure you have an Abody radiator? Never seen one that wasn't bolt in.

        I have seen aftermarket ones that need width trimming of the sheetmetal to eliminate shrouding of the radiator.
         
      • John Cailey

        John Cailey Crizila FABO Gold Member

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        Core support opening is 22 5/8" wide by 16 3/4" high. Rad core is 25" wide by 18" high. Rock Auto replacement rad for a 74 Duster with 318 motor and A/C. Don't have the hood on the car yet and height is my concern. Don't want to have to modify the rolled section on the bottom of the core support, but I might have to ( slightly ) to get the rad to sit low enough. I will bolt on the hood today and see where I am at. Drilling new mounting holes ( which I will have to do ) is not a problem. I am curious if Ma Mopar installed different core supports for the /6 verses the V8 motors? Thanks for everyone's input. Again, new to A body stuff.
        On another note, Had to shorten the drive shaft 3.5" to accommodate a 727 verses the 904 slant trans. Also slight mods to column shift linkage. Linkage did clear the headers though.
         
      • roccodart440

        roccodart440 Well-Known Member

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        SOme of the rock auto stuff fit various applications or they aren't built to exact OEM specs.

        Just throwing this out there. I'd made sure you have a quality radiator that will do the job and fit properly. DOn't skimp or play around when it comes to cooling.
         
      • MOPAROFFICIAL

        MOPAROFFICIAL FABO Gold Member FABO Gold Member

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        I remember having the same issue, I took measurements..then went to the wrecking yard and walked out with a 40.00 dollar radiator. Been using it since 2003...3 diff motors...bigger and meaner, it cools them all. I made it work by using a slant 6 hose on the inlet and a regular upper v8 hose.

        You'll figure it out, I have faith in you.
         
      • John Cailey

        John Cailey Crizila FABO Gold Member

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        Mounted the rad today. Put the hood on and checked clearance. Not a problem. Lots of hood clearance - 1.5" using clay on the rad cap ( highest point ). Used some 3/8" thick dense foam rubber between the bottom tank and the bottom of the core support. I'm good to go. Rad is for a 318 with A/C, so I shouldn't have any over-heat issues. This motor will be making slightly under 300 HP. ( my estimate ). Probably do a 16" flex fan and shroud when I get that far.

        V8 radiator1.JPG

        V8 ragiator2.JPG
         
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