1. oldkimmer

    oldkimmer FABO Gold Member FABO Gold Member

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    ........I have a 75 duster factory 360 4bbl, dual exhaust, 727 with factory hi stall converter and 3.21 sure grip......40,000 original miles.......I want to make it into the 12s.....can it be done keeping the factory long block in it with some bolt ons?..........thanks.........kim........
     
  2. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    I'm no pro on speed estimates, but I seriously doubt it.
    With forced induction maybe.
     
  3. yellow rose

    yellow rose Overnight Sensation

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    Yes.

    No forced induction needed.
     
  4. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    Well I guess that does include all of the 12's doesn't it :D
     
  5. MrJLR

    MrJLR Built, not bought FABO Gold Member

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    Juice is a bolt on....!

    Jeff
     
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    • 496 polara

      496 polara moparts id gch

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      If by bolt ons you mean deep gears,higher stall converter,headers and full exhaust,suspension work,and...........

      Probably be easier and more fun to drive by putting a 408 stroker in it and pulling the stock motor.


      It sounds like a tall order to me without sacrificing a ton of driveability and you may not make it there.
       
    • moper

      moper FABO Gold Member FABO Gold Member

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      Gear change. Engine bolt ons. drag racing suspension setup. You should be able to go deep into the 12s if the package is optimized for drag racing.

      edit - "into the 12s" won't take much in terms of the suspension. Mianly good shocks and tires.
       
    • AJ/FormS

      AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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      Howdy neighbor!
      No problem.
      Stock street suspension, or race. Springs and slicks are bolt-ons right?
      The Dc manual says 12.4s require a Power to Weight ratio of .100 with race suspension. Street suspension may be up to a half second slower, due to the 60ft challenge, and the 3.21s.
      So back to the .100 p/w
      How heavy is that car? let's say you get it down to 3500 race weight. Well then; 3500 x .100 =350horsepower. The Dc folks work off crank power so, 350 is the target. Lessee 360 cubes,350 hp, that's .97 hp per cube. Ok maybe that's a lil tuff with bolt ons.
      Since these engines seem to be 245 hp factory rated, we need 105 more hp, to just sneak into the 12s with street suspension. So I think we better bolt in some springs, gears and slicks. That reduces our p/w requirement to about .086, to just sneak in there.
      Ok then 3500 x .086 =301hp; now yer talking.
      This is doable with just a few other changes
      This combo wants to hit a hair over a hunert so 4.30s are the go to gear. They will get you 102 at 5500 with 88s(28 inch tires) and 5% slip.
      The 5500 trap points to a power peak of about 5100, and that points to 340 cam. Go get'em!
      Arm-chair at it's finest, just suck it out of a book.
       
      Last edited: Dec 18, 2016
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      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        Slicks, 4.10s and a 100 plate shot. Done.
         
      • 273

        273 Well-Known Member

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        The main problem is CR cause it limits cam choices. What's the biggest you can go with stock CR comp xe268h/xe274h/xe286h ??
        Only using comp cams as a reference

        Is stall change gonna go along with cam change ?

        How deep are you willing to go with gears ?

        Probably can get away with more cam with deep gears and more stall.

        Airgap 750 and headers nice additions.

        Nos is probably the best route for drivablity and to reach goal. Or at least can go more mild with bolt on's.
         
        Last edited: Dec 19, 2016
      • TF360

        TF360 Well-Known Member

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        I wouldn't drastically change that rare car. Get a six banger and stuff a 408 in it, or a 360 with the bolt on's. Just my opinion.
         
      • JBurch

        JBurch Well-Known Member

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        Study up on what your car would do in a stock eliminator drag class.........it runs 10's!!! 12's should not be a problem. Most of what you want to know is in the suspension, gears, converter.

        Good luck!
         
      • 273

        273 Well-Known Member

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        How about race as is an do mods as needed and see where that takes ya.
         
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        • moper

          moper FABO Gold Member FABO Gold Member

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          Compression, or lack thereof, does not limit cam choice. It does force other engine and drivetrain changes to match that cam's performance profile. Big cams are pretty irrelevant given the stock heads anyway, so just sayin'...lol
           
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          • 273

            273 Well-Known Member

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            Wasn't saying run the biggest cam but whats the biggest he can go so we know what we can play with to figure out a combo. From my understanding Xe268h would be pushing it for stock longblock. I know more stall and deeper gear will allow more latitude. He's got to find performance somewhere and intake and exhaust will add a little but the bulk would have to come from cam gears and stall plus chassis setup.

            But do feel cr does limit cam choices were all forever telling people don't go to big on cams cause of stock CR. Yes you can use gearing to cover that up a bit but most aren't will to go more than 3:55 and this OP never has said what he's willing to go with all that. Thats why I asked.
             
          • 67autocross

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

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            I would say to push a 3500 pound street car into the 12s you will need close to 400hp. My friends Duster made 380hp on the dyno and with 3.55 gears on drag radials it has never made it into the 12s, very close but not there yet.
             
          • moper

            moper FABO Gold Member FABO Gold Member

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            Gotcha. In reality though, the impediment on camshaft size is retainer clearance. On 360s with the rotators that ain't much...lol
             
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            • yellow rose

              yellow rose Overnight Sensation

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              Nope.

              Your garden verity A body needs about 290 HONEST hp to go 100-101 MPH which is 12.90's.
              My car has been almost 110 MPH and it is 340 HP.
              It's simple math.
              Simple math makes the 500 HP small block Chevy the lie that it is.


              In your buddy's example, if he actually has 380 HP, in a 3400 pound car he should be running 11.7X or so at about 111-112 MPH. Unless the HP is down or the car is heavier, that's what it should run.
               
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              • yellow rose

                yellow rose Overnight Sensation

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                BTW, what was his MPH. That is way more telling than ET.
                 
              • 67autocross

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

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                So you are saying you should go 12.90s with 290hp in a 3400lb street car? Seems a bit low on power to me to go 12s at that weight but I'm not a expert. You would think a bone stock 340 should do it as that is kind of in the neighbourhood of their stock output.
                 
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                • AJ/FormS

                  AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                  About the big cam in a lo-Compression engine
                  For a streeter this is a bad idea cuz, the low speed operation gets to be soggy on account of the low DCR. The soggy part is usually from idle to somewhere near peak torque,which on a streeter could be somewhere between 3400 and 4400. On a streeter you would be in the soggy part almost all the time..

                  In the qtr this is almost no concern cuz you only go through that soggy part one time. And usually pretty fast on account of the performance gears and the higher stall.
                  Sure the engine won't make quite as much power on the lower compression, but you don't lose as much as one might imagine.
                   
                • yellow rose

                  yellow rose Overnight Sensation

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                  A bone stock 340 was RATED at 275 but that was before power steering, all the drive belts etc.

                  It's simple math really. So when you see some joker say he has 500 HP while going 11.80's know he is either lying, stupid or his car is way heavier than he thinks.
                   
                • AJ/FormS

                  AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                  Stock 1970 swinger 340-stick cars were 14.4 second cars with 3.55s, and street tires.At least mine was. A race suspension back there with slicks and optimum gears could get you into the 13s easy enough; tire technology has come a long way from polyglass. Those engine were rated at 275, and NHRA-factored around 290. My car was 3330 with me in it. The p/w comes to 290/3330=.0871
                  With race suspensions;
                  The Dc manual says .085 is a 12.8car and .089 is a 12.6 car. So,I'ma guessing the .087 is around a 12.7 car. the manual also says that 3330/290=11.48 w/p now, should be around 104mph..
                  My car went 98 and change, in IIRC G-stock class.That was 1971. and the car was one of the quickest, not fastest, Darts around my neighborhood.
                  I think my engine musta bin a dog. But if it was so were the Hemi-Cudas which posted similar times, with a bit better mph.
                  Remember, these numbers were for SuperStock type suspensions. Street cars will need to add a bunch of time.


                  Bottom line is; people(ad companys) lie, time-slips don't.
                   
                  Last edited: Dec 19, 2016
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                  • 67autocross

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

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                    Hey you know a lot more about this stuff than I do, I was just passing on what I felt a street car would need for power to run solid 12s based off cars I have dealt with.
                    I had a 340 that made 345 hp on the Dyno that went high 12's in my 72 Scamp with an auto, I sold it to a guy who put in in a 4 speed Duster and he got it into the 12's as well. Both my Scamp and his Duster are fairly light cars with with good suspensions and a lot of weight removed, both are almost race cars really.
                    Now the 380hp 360 Duster that I mentioned in my first post is what I would call a real street car, it has a full interior and power steering 3:55 gears, 3000 stall, fully rebuilt factory suspension ect. On a good day I think it will go into the 12's but it has not done it yet, but its close. I would say a set of 4:10 gears would get it done.
                    Most of the street cars in my circle of friends that run into the 12's are make at least 350hp or more....but hey if you can do it with less all the power to yea!
                     
                  • oldkimmer

                    oldkimmer FABO Gold Member FABO Gold Member

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                    Thanks guys. I have an 8.75 with 4.30 gears. And 28x9 slicks. Also a 3ooo or so stall. I would need to get an alum intake and headers I also have a 750 carter competition carb or an 850 street demon. Kim. Hope this enlightens u guys. What cam ?would work best
                     
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