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NHRA legal solid rear convertion help needed

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Old Mar 8, 2013 | 11:40 PM
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Default NHRA legal solid rear convertion help needed

looking for pics of the mounting points and what was done with the trailing arm to make legal.
NHRA rules say stock mounting points and must use the transvers spring and that isnt a problem but i am stumped on the trailing arm to rear, is the trailing arm bored out and pass the solid rar tube trough then welded? is there a top mount to control the rear?
i cant use a 4 link for the class. so it has to be this way...
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Old Mar 8, 2013 | 11:54 PM
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Look up brent13nova, or look up 598 four link solid rear axle. These should get 20 pages of a pictorial done by brent13nova. His welding will make you feel UN skilled.
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Old Mar 9, 2013 | 08:49 AM
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Originally Posted by bluedawg
Look up brent13nova, or look up 598 four link solid rear axle. These should get 20 pages of a pictorial done by brent13nova. His welding will make you feel UN skilled.
That isn't setup while neat isn't even remotely close to being NHRA compliant. Go over to classracer.com and you will get some real answers.
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Old Mar 9, 2013 | 01:35 PM
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Didnt know that. Iirc, he did that for drag racing his vette with the 598 he was going to put in it.

Last edited by bluedawg; Mar 9, 2013 at 01:42 PM.
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Old Mar 10, 2013 | 01:30 AM
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[QUOTE=john@ATI;
NHRA rules say stock mounting points and must use the transverse spring and that isn't a problem but i am stumped on the trailing arm to rear, is the trailing arm bored out and pass the solid rar tube trough then welded? is there a top mount to control the rear?
i cant use a 4 link for the class. so it has to be this way...[/QUOTE]



What class are you trying to set it up for? NHRA Stock or Super stock?
It would help knowing whether the car is being set up to run NHRA Eliminater class's or just be NHRA legal for the ET.

Are you asking how to attach a solid axle to the original trailing arms?
If so you can't. What the rules state is that you must use the original control arms mounting points. You do this by using the original type of control arm, rear transverse spring AND Half shafts. You will need to run half shaft safety loops. (2) per side, plus a drive shaft safety loop.
This can be mounted to the rear cross member at the front of the drive line. Rules will state a position relative to the forward u-joint.

Overly Stiff rear spring, adj. bump stops, double adjustable shocks, rear cross member support pads, something to eliminate camber gain and upper links that remove the load on the half shafts. Just of few of the techniques use to run the IRS and keep it class legal.

Post a clearer example of what you are trying to do in the Drag race section. I think you will get more defined feed back once it is understood what you are trying to accomplish.

Dave
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Old Mar 10, 2013 | 11:53 AM
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John, PM me your email address. I have some pics it took of a C3 Super Stock set up last fall at a race. They aren't the best pics, but they are the best I could get with the car on the ground.
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Old Mar 10, 2013 | 05:41 PM
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I guess you weld some trailing arms to the rear housing after you have all the angle perfect.or you could notch the bottom part of the trailing arm and slide a axle housing in from the bottom,you could use heavy straps or big U-bolts to lock in the correct angles.
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Old Mar 11, 2013 | 01:30 PM
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Make yourself some ladder bars to replace the trailing arms. Weld the mounting point on the rearend axle tubes with a flat plate at the bottom to mount the end of the transverse spring along with a bottom shock mount, top of the shock just bolts in the original location. The ladder bar will control both front and back movement along with axle wind up. Nothing needed off the center of the rearend for axle windup. Extend down from the original crossmember center mounting point to the center of the transverse spring, this will control any side movement.

This keeps everything mounted off original frame mounting points.

Last edited by Little Mouse; Mar 11, 2013 at 01:48 PM.
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Old Mar 11, 2013 | 02:00 PM
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John, as suggested, go to classracer.com for the most up to date interpretation of the "stock" rules. Be patience, stock is a VERY competitive class and guys may be understandably reluctant to share info. You will also find racers generally willing to share experience in person,show their setup at the NHRA/IHRA races. Joe.
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