Torsion Bar size for Drag Racing

Suspension, Steering and Chassis

  1. 72DMag

    72DMag Well-Known Member

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    Hi all,
    Building a 72 duster drag car. Car is being setup for 1/8 mile with a 451 and 4.88 gears with dana 60. The car currently has .850" torsion bars. Given the B block and that this is a drag car are these torsion bars good enough or too small? I've heard of guys using the slant six bars for drag racing but not sure if thats true or not.
     
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    • Garrett Ellison

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

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      MPs drag race bar is .81, which is even smaller than the slant six bar. But in a dedicated drag race car, you’ll be okay. Smaller bars have to be cranked tighter so it makes the suspension top out quicker with drilled out or drag shocks.
       
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      • Plymouth 65

        Plymouth 65 Floorable Deplorable

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        Don't forget the ss rear springs. Old school setup! 65'
         
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        • dukeboy_318

          dukeboy_318 FABO Gold Member FABO Gold Member

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          Smaller the bar, the better the weight transfer to the rear wheels, in long held practice and theory anyway. If its a strictly strip car, slant 6 bars will work just fine and you can nearly get them free if you dont have them already.
           
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          • ir3333

            ir3333 Well-Known Member

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            small bars are best has been accepted for a long time....but no matter what the twist rate of the bar, the weight of the front end is the same so i always wondered about it?
            A friend has a 68' hemi SS barracuda that runs lo 8's and he says stiffer is better.
             
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            • Garrett Ellison

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

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              In most cases the thinner bars are used in conjunction with drilled out shocks and the upper control arm bumb stops removed. The idea is that the front suspension unloads completely before building enough momentum to pull the front tires off the ground. It probably matters more with super stock springs than with ladder bar or four link rear suspension, but stiffer bars are a good thing when the front of the car comes back down. A thicker bar not wound as tight lets the front end settle back down a little more smoothly. I really don’t think think that thin bars are going to be significant advantage in anything that carries the front wheels for any distance, which shouldn't be a problem for a stout 451 and 4.88s gears.
               
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              • 72DMag

                72DMag Well-Known Member

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                Eventually it would be nice to have this car as a pro street setup but its far from that. Sounds like I have a decent size torsion bar to start with. Only thing to do now is test and see how it launches. Thanks all!
                 
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