Trust your alignment guy, why would he lie. Its the way the cars are made.

I don't think that he would lie, just that he might not be qualified. The addition of the offset bushings resulted in less than 1 degree of caster? Really? My 70 Charger is a shade under 5 degrees with essentially the same parts. I understand production line variances but that seems excessive.
The owner drives the car sparingly since buying a Challenger R/T in 2012. He may not care a whole bunch. I'm just curious about this because I've had much better luck with other cars.

A thought about production line tolerances: perhaps it has as much to do with the plant that assembled the unibody? Maybe some had jigs that allowed more performance oriented alignments?

And my thoughts on alignment specs here: for street driving, caster is far more important than camber. The reality is that youre more likely to notice the self centering afforded by caster than the extra grip from the camber. Racing is a different story, especially autocross.

To those that have a hard time achieving caster, is the rear ride height boosted over stock? Changing the angle of the car will affect caster, a lower rear ride height will improve caster.

Has anyone ever done away with the cams and lengthened the slots to allow more adjustment? The cams are strictly to ease adjustment, once the bolts are torqued they dont do squat.

Let me re-state my original post above, that is, I have never got more than another .5 degree castor with offset bushings. That's on 4 cars, two mine, two not. I do my own alignments and have done this for friends also. Cars with .5 degree castor seem to drive and ride fine, but we'd like more. If you actually have 5 degrees of castor from factory, that would be extraordinary, but of course entirely possible.

On the aftermarket upper arms I bought, without modification, max castor I could get was 5.5 degrees. That is, one rod arm out as far as safe, the other all the way in. AND, driving around on the street, although not much, you couldn't tell the difference from before. I would do about 95 in the 1/8 mile, and this was done for racing. What I didn't know at the time, is all of this castor was done to fix a car that wouldn't go straight because of rear tire run-out.

Somethings you find out a little too late.

Let me re-state my original post above, that is, I have never got more than another .5 degree castor with offset bushings. That's on 4 cars, two mine, two not. I do my own alignments and have done this for friends also. Cars with .5 degree castor seem to drive and ride fine, but we'd like more. If you actually have 5 degrees of castor from factory, that would be extraordinary, but of course entirely possible.

On the aftermarket upper arms I bought, without modification, max castor I could get was 5.5 degrees. That is, one rod arm out as far as safe, the other all the way in. AND, driving around on the street, although not much, you couldn't tell the difference from before. I would do about 95 in the 1/8 mile, and this was done for racing. What I didn't know at the time, is all of this castor was done to fix a car that wouldn't go straight because of rear tire run-out.

Somethings you find out a little too late.

Also, I have had to grind off the back inside of the upper control arm as with the cam turned all the way in board with offset bushing, the arm would hit the inside of the "shock tower".

Would some of the problem be with the k-frame to far back? How far moving it forward would it take to help the problem (elongated holes in the k-frame) just thinking out load here.

I'm thinking the deck is stacked against you when you are dealing with sub-par assembly tolerances from the 60's&70's. It doesn't help on the friday or monday cars that were put together by someone who was having issues at work that day and not being able to check fitment before pulling the trigger on the welder. I know even on newer stuff like the 4x rams, the mounts for the upper and lower control arms can be off like 1/4"+ which contributes to the famous "death wobble". You have to resort to adjustable arms to alleviate it as the stock stuff only allows for minimal adjustments. The adjustable arms and strut rods are a big boost for our old cars, but what do you do if you can't get enough adjustment to get you where you need to be? I'm wondering if in those instances, you will have to move the pickup points for the suspension mountings. Also, if you are off only a small amount at the arm or part attachment, with the stack up of other issues and that the defect is magnified the farther out it gets from the pivot or attachment point, you are going to have a fun time fixing things.

Great questions. I agree that caster is the main goal for a mild street type car. The problem that I am learning is that gaining caster means also gaining positive camber. I am still curious about some possible fixes. The owner called me to say while the rear cam bolts are maxxed out to the inside, the front ones appear to be near the middle of their adjustment range. When I had the car here, I had the fronts cranked to the outside and the camber was WAAAAY positive. This has me wondering if those spacer washers from Mancini would be a way to reduce the excessive positive camber. (In effect, resulting in less than the 2 degrees of NEG camber that they are advertised to provide)
The same alignment shop had trouble aligning my FrankenDuster in 2011. I had these same bushings in that car, installed the same way. I chalked it up to a shop being NON Mopar friendly or possibly just unwilling to work on an old car. The Duster was also "Baseline/Bonehead" aligned by me with the front cams out and the rear cams in. It tracked and steered great with no abnormal tire wear.

That is entirely possible. Incorrect positioning either by damage or incorrect placement of the frame mounted captive bolts would certainly affect caster. Incorrect placement of the UCA mounts would too.

If those were the arms out of my car, I got about 6.5 degrees positive caster with .5 negative camber with them with no other modifications but lowered ride height. They should be good to go....

The thing that sucks with doing Mopars is that most alignment places don't want to spend the time to get it really spot on which is why I ended up doing it myself at a friend's shop

I have an alignment gauge if you want to try and do it at home. Let me know and I can bring it to the meeting on Thursday

I do not find you to be annoying.
Also, the meeting is on Tuesday.
Can you hear me?

Today we tried shimming the power steering pump to reduce the pressure for better road feel. After reading several posts here and elsewhere, we agreed on a total of .125 thickness. I have read of some going as high as .140 with good results so I figured that .125 would be a good starting point. It turned out to be too much! Once rolling, the car steered fine but with the car sitting still, the steering wheel went about 1/3 of a turn then got too hard to turn without using both hands.
He plans to step back to .100 or so and reevaluate.

I've had mixed results using the offset UCA bushings installed a'la Mopar Action. Due to the exaggerated location points you can get with this set up I've found you really have to tighten the lock nuts much more to keep the cams set. Even then I hear a little popping and creaking out of the uppers. I've also found that A bodies seem to allow 360 degrees of rotation on the alignment cams, whereas a 70 E body seems to hit and limit you to 180 degrees. And this doesn't seem related to the offset bushings themselves, as that same limitation was there with stock bushings.They would hit while turned all the way in. I understand a 71 E and B body share front frame rails and might expect that same limitation on a B body of that age. With an A bdy I seem to be able to get the caster/camber I want with the bushings - not so with the E body. I suspect it's because of the lack of 360 degree adjustment. What worked for me on an A body was setting the camber first using the back cam, then adjusting the caster with the front cam and moving the camber back with east caster change.

Funny that you should mention the strange interference while rotating the cam bolts. I found the same thing with this car. Its as if the bolts have egg shaped washer/eccentrics. I had to back them out a bit, clock them, then drive them back to get full 360 degree spin. I don't recall having to do this on my 70 Charger or any A body that I have ever worked on.

Yea, they do act as eccentrics by placing the through bolt off to one side - that's what moves the arms in or out as they push against those raised areas that capture the eccentrics. I've seen the same set up on late 60's early 70's Mustangs but on the inboard lower control arm mount. I found the e body upper ctl arm hits at about the 10 to 8 o'clock inboard position on an E body.

This bind or noise is probably the rear part of the A arm rubbing on the shock tower. I mentioned this above that you have to grind/cut off the inside part of the arm to make it work. This will also keep the cams from making a full turn.

In all of this, without going any further, if you have 1 degree, I bet it will drive and ride fine! Try it. If it doesn't, you have loose, worn, or bent "stuff". There may be a ton of ways to compensate, but no need to do so.

I use offset bushings everytime for this exact reason. I've done alignments for over 40 years. Many times even with the bushings ideal caster is not obtainable. You also have to remember that any chassis rake effects caster, rear end up reduces it
Additionally think about what happens to the toe pattern when you add too much positive caster. It lowers the outer tie rod and can create an undesirable toe pattern. Personally 2.5 degrees seems about right. My 64 Belvedere drag car regularly runs close to 150 mph with stock parts and 2.5 degrees without issue. This was achieved with off set bushings in the front location and shortening the strut rods .375.
Doug

The other day I started thinking that to get where he wants to be, it will take a few tricks, not just the bushings. My current plan is to add the lower ball joint spacers to add negative camber, then adjust the front adjuster cams further out to gain caster. The strut rod bushings are urethane. I can shave 3/16" from the inner strut rod bushing and pull the LCA forward some. This should provide enough to get there.
I was either lucky before or the other cars I had were on the other end of the tolerances. I have been able to get the numbers simply with the special bushings.

[quote=Frankenduster]The other day I started thinking that to get where he wants to be, it will take a few tricks, not just the bushings. My current plan is to add the lower ball joint spacers to add negative camber, then adjust the front adjuster cams further out to gain caster. The strut rod bushings are urethane. I can shave 3/16" from the inner strut rod bushing and pull the LCA forward some. This should provide enough to get there.
I was either lucky before or the other cars I had were on the other end of the tolerances. I have been able to get the numbers simply with the special bushings. [/quote


just came to me about the spacers... Not the ball joint stud but the bolts that hold it to the spindles, right?

Yes, that is right. They tilt out the bottom edge of the knuckle/spindle. The ones from Mancini racing are said to result in 2 degrees of negative camber. They look to me to be around
3/16" thick. That is more that we need, so I'm thinking of using thinner ones, yet still grade 8 for strength. I figure if 3/16" is worth 2 degrees, the 1/8" ones I can get would result in 1.3 degrees. Since outward adjustment of the front alignment cams to gain caster also results in a positive gain in camber, I think it should work.