s/s springs & front sus?

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dart72a

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I've relocated the rear springs on my 72 swinger and installed solid aluminum bushings up front on the s/s springs. I have a pair of stock shocks and the adjustable snubber is off. I've tried running the snubber at all heights and the car does not hook. The best and most consistent 60's has been with the snubber off (1.51 to 1.54). The front of the car has the factory suspension with slant 6 torsion bars. All the bushings were changed a few years back to urethene and there is a set of 90/10 Comp Eng shocks up front. The front suspension height is set to factory (1 5/8"). Oh by the way this is a 340 car. Now since I've relocated the rear springs and the rear works better, I've got the problem of "porpusing". The car will actually lift the left front off the ground twice about 4 to 6 inches. My friends at the track are telling me the front and rear suspension are not working together. One MOPAR racer said to put a little taller tire up front and lower the suspension about 1", this would give me a little more travel. Other racers say its all in the shocks but I've tried adjustables in the rear. I've even checked to make sure that the shocks both front and rear are not bottoming out. Is there anyone out there that can point me in the right direction?
 
i think you need a longer than stock shock in the back. ss springs will reach the extension limit on stock length shocks. try the mopar drag shocks, ones out of an imperial or a pick-up truck.
 
Do you have any pictures of the car upon launch or maybe some video so we can see exactly what its doing? You said you checked to see if the shocks are reaching full extension did you do that by jacking up the body disconnecting the shocks and letting the rear hang? If so the SS springs on my car bow a lot more under load so a longer than stock shock is a must. What direction are your rear shackles facing when the car is at rest? Have you tried aftermarket clamps on the front half of the spring? When you stage are you taking all of the slack out of the suspension before you launch negating the "shock" style suspension? Try a home made spacer on the front shock giving you another inch or so of travel and see what effect it has? Hope this helps:)
 
Some of the adjustable shocks don't do anything until you have several clicks and then the adjustment is more than what you were hoping. Call Cal Tracs. They have a nice Rancho set up. They will help sort out the problem. When you pull the L front it can be an indication that the weight bias on the front suspension is off. Road racers try to balance out each of the four wheels. This can help focus on any suspension base issues.
 
im not positive but believe you need at least a 28 fully extended shock for the ss springs ,then get a good set of adjustable coil over shocks
 
allowing the pinion to bottom out in the transmission with no snubber could spell disaster. use the snubber, for 4 speed car snubber should be just hitting frame for auto leave 1/2 inch 28 inch extended shocks with adjusters and coilovers will do the trick with ss springs,I use a welded threaded rod ,cut the rubber off snubber plate ,reinforce the frame ,weld the rod to frame and to top of snubber frame, this also allows me to adjust my pinion angle, very similar to a tractor top link but very effective.
 
jack the car up and put some jack stands under the frame rails. disconnect the rear shocks, Let the rear suspension hang. Now measure the distance between the top shock mount and the lower shock mount.


If your shocks extended length is shorter then that distance then you risk the chance of running out of shock travel and unloading the tires.

You need a shock that can extend at least the amount.
 
1 5/8th front ride height makes no sense as your front suspension and and oil pan would be scraping the ground.do you know where the point to check front ride height is and what factory calls for? 1 5/8 first for me ,your measuring wrong area or you got it slammed to the ground, ask if you want to set it right and where it is done ,and how,regards
 
didnt know a 340 oil pan would clear the slant 6 centerlink, normally a v-8 link is used. my 6 with a bigblock hit the back of the pan before changing over to v-8 link, now it almost touches. yes, the rear of the pan hit with the front sump type pan not a rear sump type. your engine must be sitting super high in the chassis , which actually is a good thing for racing
 
I apologize, I misread your question. the 1 5.8 suspension height is correct. Ive also seen bigblocks using the milodon using a motorplate using the 6 centerlink.check your ride height by parking on a level surface ,correct tire pressure.bounce the front end a few times to settle the suspension. measure the distance from 1 adjusting blade to the floor,and then measure the distance from the lowest point of the steering knuckle arm,at the centerline,on the same side to the the floor. the difference between measurements is the ride height. from side to side there should be no more than 1/4 difference. you are correct on the 1 5/8 number . fully extended with ss springs you should have minimum 28 inches fully extended . definitely buy the longer shocks as this is where your trouble lies. slant 6 t bar works great for a small block, small block t bar works great on a bb car for racing. Ive seen t bars on slant 6 cars on A bodies ,from the factory, that have thicker tbars then 340 original tbars in A bodies, buy the m.p ss extended shocks from jegs and problem solved, them ss springs will then plant like a gang of illegal mexicans, also use the m.p. adjustable snubber , auto car leave a 1/2 inch gap ,manual leave it to where rubber just touches pan ,you may have to cut the snubber rubber to get it right but by not using the snubber your winding the axle , also check your pinion angle, should be between 3 and 7 degrees ,I set mine at between 3 and 5 depending the combination, sorry, didnt mean to offend you friend, take care.....make adjustments by turning adjuster bolt near the top of the lower control arm,
 
what I shoot for is around 7.5 inches from lower ball joint housing to floor, much easier and it works on the earlier models quite well
 
Dont know if this pic helps but this is my sons 72 Dart launching. This car is all stock suspension other then the 002 & 003 SS springs. It has all the original 318 suspension up front (but we rebuilt it) and the springs are in the stock location in the back. It is a .030 over 400 street car with 3.91's and a Hoosier QTP 26 x 9.5 x 15's in the rear. Has a 727 with a Dynamic 9.5 convertor that flashes about 4200. Like I said it is a driver street car and usually 60's in the mid to low 1.60's with a best of 1.61 and a best et of 11.45 @ 117. But the car dead hooks and is very consistent. This is a very low budget car and like I said the suspension is all stock other then the SS springs so there is no tricks here but it does hook good. Ron

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383 man ,good to hear about a standard stroke 400 engine, or i presume it to be. Gotta love them 400s best block ever built by any of the big factories. what type cam are you running in it cause thats a whole lot of converter . take care. happy easter
 
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