New SFI magnum Flex plate coming soon.

Magnum Engine Swaps

  1. mopar65

    mopar65 Well-Known Member

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    So there has been a little buzz and I didn't want to release anything until it was basically ready...but here it is.

    Do you have a Magnum engine making (or expect to be making) north of 500 whp ? Are you worried about breaking the factory flexplate , or maybe you already have?

    With the help of our partners, we are releasing a SFI certified Flexplate. At last, we will have a flexplate capable of tolerating all the power your Magnum small block can handle. No more worrying about a chunk of steel flying out as you spin your small block to 7000 rpm.

    We are looking for one guinea pig for road testing ...
    We expect to be selling this as part of a package with either a blanket or a scattershield.

    #screenshotthis
    #homeofthefastmagnums
    I got this off my magnum engine group on Facebook.
    It's about time somebody started making these again. I am going to buy one when they are ready for sell.
     
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    • mopar65

      mopar65 Well-Known Member

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      FB_IMG_1552244709368.jpg
       
    • 03JeepJeep

      03JeepJeep It's a hoot!

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      Interesting, love to see some new stuff come out for these engines.
       
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      • 67autocross

        67autocross A new iron curtain drawn across the 49th parallel

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        Anyone have a link to the magnum flex plate?
         
      • ed1946

        ed1946 FABO Gold Member FABO Gold Member

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        Heres his web site www.frptuning.com
         
      • Bobzilla

        Bobzilla Well-Known Member

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        Anybody know if this was true? I still don't see anything on that website and I don't do Facebook.
        I have not called about it because I had to put off my projects. Just wondering.
         
      • 67autocross

        67autocross A new iron curtain drawn across the 49th parallel

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        I ended up making a flexplate with a template I got off I guy from this site
         
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        • Bobzilla

          Bobzilla Well-Known Member

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          I looked at my conversations. That was me, back in May. Did you get it running with the one you made with the template?
           
        • 67autocross

          67autocross A new iron curtain drawn across the 49th parallel

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          And a big thanks again for that template! As far as the engine I’m tied up with some other projects so it’s sitting at my friends shop waiting to go on the dyno.
           
        • Bobzilla

          Bobzilla Well-Known Member

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          Hopefully I can test mine out by April or May. I am way behind on everything right now.
           
        • RAVano

          RAVano Well-Known Member

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          Are the Magnum flexplates different then the LA ones? Can't you just use a SFI flexplate for a LA on the Magnum?
           
        • 70aarcuda

          70aarcuda Master Hoader of SBM FABO Gold Member

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          What is different is the amount of weight balance....the magnum takes less external weight for the balancing....I have a B&M magnum flexplate and the area of cut out is smaller then the LA 360 externally balanced flexplate....I bought it so i can use it as a template also....
           
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          • RAVano

            RAVano Well-Known Member

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            So the internal balance 5.2 flexplates are compatible?
             
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            • MRGTX

              MRGTX Well-Known Member

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              Has the flex plate ever been a weak link here? This sounds like a problem that I didn’t even know that I needed to worry about.
               
            • Bobzilla

              Bobzilla Well-Known Member

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              5.2 Magnum is basically internally balanced, so it takes neutral converter and neutral flex plate. No problem.
              5.9 Magnum is external balanced and it's different than LA external balance.
              SFI rating meets race sanctioning rules for safety.
              Any street car can just run one made from a template or fabbed from something else.
              The stock 360/5.9 Magnum flex plate works on mild builds for the street, but a stronger one is a good idea when pushing around 400 HP or more.
              Any 360/5.9 Magnum that has been balanced internally, such as aftermarket cranks, no longer needs Magnum specific balance parts.
              If I missed anything, feel free to comment.
               
              Last edited: Jan 19, 2020
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              • 70aarcuda

                70aarcuda Master Hoader of SBM FABO Gold Member

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                5.2 is internally balanced....5.9 is externally balanced...so the answer is No...unless the weight is on the converter...lol
                 
              • motorcitymagnum

                motorcitymagnum Active Member

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                5.9l magnum with 904 is my setup. still a cast crank(external balance). was hoping to find correct flex plate for this but I think ill go neutral plate and have weight added to converter. I have reached out to flying brian and no response yet. keep in mind that 360la plate/converter has off set lugs. 5.9l magnum flexplate and converter(stock) are not off set, from what ive been able to find

                building 408, which will be internal balance, but wont be finished until late summer.
                sfi is added insurance for sure!
                I also run trans blanket just in case.

                thanks! motorcity magnum
                 
              • Jadaharabi

                Jadaharabi FABO Gold Member FABO Gold Member

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                On the LA motors using the B&M plates doesn't the 904 use a smaller diameter flexplate than the 727 so that the starter clears the flexplate.
                 
              • Bobzilla

                Bobzilla Well-Known Member

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                This was my understanding for 904 as well, but I don't have a 904 torque converter to mock it up. LA or Magnum just changes the balance weight, and 904 or 727 changes the diameter. I could be wrong.
                 
              • mopar65

                mopar65 Well-Known Member

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                I messaged Ryan a few times my self and never really got any aware. My stock 5.9 magnum flex plate was cracked and I needed a new one. I was wanting to install a SFI one because my 96 dakota will run low 7 in the 1/8 mile. But not having any luck I just installed another stock one. I am using a conan 8 inch converter with my 904 transmission. All I had to do was file out one of the bolt holes like everybody else does. Anybody know why B@M stopped making them? Also could somebody make a template for me. I would pay for shipping etc. I mean I was going to buy a neutral balance B@M SFI and cut out the spot for it to work with the cast crank 5.9
                 
              • Bobzilla

                Bobzilla Well-Known Member

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                Not sure if there is enough room on an 8 inch converter, but you could just transfer the balance weight itself from the old flex plate to your converter. Good welds required, of course. Then just run a new sfi approved neutral balance flex plate.
                I can send you a template of a B&M 10242, which is correct Magnum balance, but it's supposed to be for 727 transmission. I don't have a torque converter for the 904 transmission I have to test for starter clearance. I don't know if it will have clearance in a 904 application. The B&M flex plates are a little smaller diameter for the 904, at least I thought they were.
                 
              • mopar65

                mopar65 Well-Known Member

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                Good point that I am not sure off. The coan uses the 7/16 bolts if that makes a difference. I was just going to take a neutral balance uncut flex plate and then take the template and cut the notch out for the 5.9 magnum balance. But I for got about the 727/904 flex plates being diffrent. Sounds like I might just be better to keep using the stock ones until somebody comes out with the right one. Lol
                 
              • mopar65

                mopar65 Well-Known Member

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                Here is a pick of the old one with the crack next to the new one. I am not sure if you can see the crack in this picture

                20191127_224319.jpg
                 
              • Bobzilla

                Bobzilla Well-Known Member

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                If the stock Magnum flex plate is clearing everything and working for your 904, I'll just compare the diameters. Then we'll know if making one from a 10230 neutral balance 727 flex plate will work for you and I'll send a template.
                I may not get back to mine until Saturday to compare it.
                Adding that I did measure bolt patters on 10242 and 10230. Both have the large 11 1/8 inch pattern for 5/16 inch bolts on large 727 converters, and both have two 10 inch patterns for more common performance converters, one with 5/16 inch bolts and one with 7/16 inch bolts.
                 
                Last edited: Jan 23, 2020
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                • motorcitymagnum

                  motorcitymagnum Active Member

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                  so this is where I stand:
                  still running cast crank(external balance)
                  correct balancer(sfi and changeable for internal/external balance)
                  tci flex plate (neutral) six bolt crank and 7/16 holes for converter bolts)
                  turbo action converter for 904. 10" with slightly off set bolt pattern
                  weights to be added to converter for magnum balance.
                  this set up will easily let me change to internal balance stoker, later this year. simply remove weights from balancer/converter and use tci plate.
                  motorcity magnum. thoughts/comments? weights are showed for reference only. pic 1.jpg pic 1.jpg crank 1.jpg

                  plate 4.jpg

                  plate 4.jpg
                   
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