The Dodge Challenger Message Board

I need help!!! Please forgive me if some of my terminology is incorrect as I am not a true mechanic, just someone who’s tryin to get off the couch and stay busy workin on a project with my son. Since we are Mopar fans we have got our hands on a 70 Challenger that’s pretty straight and were goina do a ¾ ground up restoration on it (not concourse). The car is an original 318 3-speed car. We have built a solid 440 and purchased a new automatic Turbo-Action transmission with a reverse-shift manual valve-body in it. We run a 72 Challenger about 10 years ago at the local track with a similar setup. We want to make this car more of a streetcar with nice handling and a good ride but power on demand as needed. We have just finished a complete rebuild of the front end including all tierod ends, all control arm bushings both upper and lower, ball joints, idler arm, strut bushings, along with installing a sway bar. Herein lies my question; we also ordered the 440/426 Mopar Performance heavy-duty torsion bars. The service manual that we used said to make sure to keep the L one on the driver’s side and the R one on the passenger side and we did. It also said to make sure that we installed the torsion bars with the slot on the end in the same location that it was in when we took it out. Again, we did that. My problem is that I am too big to get under the car and the person I had helping me says that the torsion bar will only go in only one way and that’s where it was before with the alignment mark on the back. This caused the height adjustment to be straight up and my adjustment nut bottoms out and still does not touch the height adjustment bracket. Therefore my adjustment does not touch the frame and the car sits on the ground. When we pull the torsion bar out and lower the adjustment bracket the guy helping me under the car says that we can not get the torsion bar to go into the boot because it will only go in one way. Is this true or do we just need to make it fit? Is there something that I’m not doing that I need to do? Help!!! Any advice would be much appreciated. Big Mic

Ok big fella. Let me see if I can figure out what you are doing wrong here.

I don't think it matters (someone correct me if I am wrong) which way around you install the standard torsion bars as I think there is no offset between the ends, i.e. the hex at one end is perfectly in line with the other end.

Custom uprated bars have an offset that makes it necessary to install them the correct way around or you would get the sort of trouble you are getting.

To install them you need the front end raised (with the wheels off helps) so that there is no weight at all on the front suspension. Push the bar through the rear hex socket in the crossmember and then on into the lower control arm. You should have the height adjustment screws and the plate they screw through removed. You now need to rotate the pivot so that it locates onto the torsion bar but is positioned so that the adjustment screw and the plate that holds it into the lower control arm can only just fit in under it. Now when you start screwing the adjuster in it will meet the arm on the pivot and hold your car up.

Good luck.

I am going to do this upgrade this weekend, along with my new bushings and ball joints. Man, the new torsion bars look trick.

Now, I have a question. These new bars are 1.040 diameter. The ones I am replacing are .870. Lots of difference! I think the 440 is suppose to be .90 or .92. What is this going to do?

I thought you said you were running the small block size? (0.88inch) The correct time to ask what it will do to your car is before you buy!

Well by using my maths spreadsheet (on my web page) you can work out the spring rate for each of these.

The 0.88" bar gives you a wheel rate of 120lbs/in.

A 440 (0.92") bar will give you 144 lbs/in

This new bar you have (1.04") will give you a wheel rate of 235lbs/in.

That is a big increase!!!

You have gone 50% higher than what you have now, 40% higher than a stock 440 spring.

Are you sure the bar is 1.04"? It does seem very large.
I use a 1.00" bar and that small difference means mine is rated at 'only' 201lbs/in.
So my bars give me a 30% increase in the spring rate at the front compared to my original 440 bars.

I had to then increase the rear spring rating by the same amount. This was complicated by the fact that I also moved the springs in at each side. That decreases their rating because as the spring is moved away from the wheel centre the lever arm forces on it are greater. So it took a lot of pencil on paper work to work out exactly what the rating on the rear should be. I seem to have got it about right. However I did not get the amount of camber in the rear spring correct and I had to have them re-treated to give them the right height when the car is standing.

Oh. I forgot. You also have to take the rate of the front and rear sway bars into account as well.

Get it all right and your car will go around twisty roads very flat and pull high 'g's on corners with no understeer/oversteer.

We had our car out on a very twisty road yesterday that went up and down almost as much as from side to side. The Challenger did VERY well and even though it is quite low it did not scrape the ground even when almost flying over hills in the road. Yet it does not feel that stiff when driving.

These are 1.030. And I cannot get the pivots or torsion screw anywhere near going in.

YOU CHANGED THE SIZE OF THEM AGAIN!!!

First of all you have got 0.88 bars then they are 0.87. Then you buy 1.04 bars and now you say they are 1.03 bars. Have you been rubbing them with wet'n'dry overnight or something?

Of course they will go in. Bars this size have an offset twist so unlike the standard bars you have to be very careful about which side is which and which end goes at the front and which to the rear. They are stamped on the end to tell you.

Take the adjuster screws and the little plate the screw goes into out of the lower control arm completely to help you. You can fit them back in once the bars are in.

BigMic never got back to us to say if he worked it out OK or not.

well, I tried and tried and tried,snif, and now the old ones are back in. The adjustment was just way off. I laid them on the ground and the bar laid flat, to there was no offset. NONE! The reason for the difference in measurements is that I was measuring over the epoxy paint. I am going to send these back I think, unless they will not take them back. BTW,I did order or thought I ordered the correct ones for the 440. I guess I did not hear the exchange where the sales person was telling me these were oversize. So, when I pulled them from the package this morning and measured them,I was a bit surprized.

BTW, I did find the "clunk". It turns out that the previous owner must have run out of the proper bolts for the shocks and used 5/16th. That was the clunk.

It all seens very strange...

I tell you what though. I do remember this much from when I did mine. I remember thinking that they do not line up right but when I got it on the ground it was fine.

Wish I could have been there to have a look and lend a hand.

I wish you could too. There is no way that this unit will line up. There has to be 1/2 of a flat off to line up. And I tried all combinations. I will be contacting the supplier tomorrow.