I can't speak to a '69 but on the earlier cars the recommended specs are:

Caster: 3.5 to 5.0 degree Positive
Camber:  0 to .5 degree Negative
Toe:  1/16 to 1/8" Toe IN

With a 69 you may be able to get near that 5.0 degrees Positive on the caster...but it's pretty much not possible on a 65 - 66 without the Arning drop and even moving the UCA to the rear one turn on the shaft.

Good luck

BB
 

Get rid of the lowering springs and do the Shelby/Arning drop.  The problem with lowering springs is that they negatively modify the suspension geometry.  A lowering spring lowers the car by moving the suspension upwards.  This changes the static angle of the upper and lower control arms, as well as the angle and operating arc of the tie rods.  You will likely get bump steer as a result of using lowering springs without some way to correct the tie rod angle (taller tie rod ends, or an adjustable height tie rod end system). 

Then, you still have the issue's that were present in the stock suspension geometry, namely that there is a tremendous amount of camber gain as the suspension cycles.  What this means is that the tire may have a good contact patch sitting static, but as the suspension loads the top of the tire moves outward and the contact patch gets smaller and reduces road grip.  This is the primary reason why these cars plow like a pig through a turn stock (understeer).

The Shelby/Arning drop both corrects the poor suspension geometry and lowers the ride height.  Its all win, with no negatives.  It greatly reduces camber gain, improves positive caster, and keeps the tie rod operating angle stock.  Lowering springs move the suspension up into the body; the Shelby/Arning drop moves the body down onto the suspension.

A performance alignment will be much easier with the Shelby/Arning drop.  Without it you better set up for about 1.5 degrees of negative camber to get any kind of handling, and positive caster adjustment is going to be limited to maybe 2.5-3 degrees.  With the drop you need about 0.5 degrees of negative camber and 3.5 degrees of positive caster is easily achieved (though more is great if you have the adjustment).  I would add 0.25 degree more positive caster to the RH side to account for road crown. 

Alignment specs with the drop:

Camber 0-0.5 dgerees negative
Caster 3.5 or more degrees positive (if you have manual steering the more you add the harder turning the wheel will be)
Toe 1/16" toe in per side (make sure you start with the centerlink centered in the car, you can't go by the steering wheel placement as it may have been altered at some point)

If you can't find a reputable alignment shop that works on old cars I'd advise learning to do the alignment yourself.  I use the Fastrax system and align all my own vehicles after being continually disappointed in the alignments I got at local shops.  The big chains (NTB, etc.) by and large are not good places to take a classic.  They run on volume not precision.  You want a shop that will align it to the specs you give them, and know how to make the adjustments to a classic mustang.  Unfortunately, like our cars these shops are fewer and fewer each year, as are the alignment techs that understand them.  If considering a local shop get referrals from forum members or local car club guys.  Honestly, if you work on your own car there's no reason not to learn to do your own alignment.  Its really not some black art; it just requires an understanding of what the adjustments are, how to make them, and how what you're doing effects the cars handling. 
 

TKOPerformance wrote:

Get rid of the lowering springs and do the Shelby/Arning drop.  The problem with lowering springs is that they negatively modify the suspension geometry.  A lowering spring lowers the car by moving the suspension upwards.  This changes the static angle of the upper and lower control arms, as well as the angle and operating arc of the tie rods.  You will likely get bump steer as a result of using lowering springs without some way to correct the tie rod angle (taller tie rod ends, or an adjustable height tie rod end system). 

Then, you still have the issue's that were present in the stock suspension geometry, namely that there is a tremendous amount of camber gain as the suspension cycles.  What this means is that the tire may have a good contact patch sitting static, but as the suspension loads the top of the tire moves outward and the contact patch gets smaller and reduces road grip.  This is the primary reason why these cars plow like a pig through a turn stock (understeer).

The Shelby/Arning drop both corrects the poor suspension geometry and lowers the ride height.  Its all win, with no negatives.  It greatly reduces camber gain, improves positive caster, and keeps the tie rod operating angle stock.  Lowering springs move the suspension up into the body; the Shelby/Arning drop moves the body down onto the suspension.

A performance alignment will be much easier with the Shelby/Arning drop.  Without it you better set up for about 1.5 degrees of negative camber to get any kind of handling, and positive caster adjustment is going to be limited to maybe 2.5-3 degrees.  With the drop you need about 0.5 degrees of negative camber and 3.5 degrees of positive caster is easily achieved (though more is great if you have the adjustment).  I would add 0.25 degree more positive caster to the RH side to account for road crown. 

Alignment specs with the drop:

Camber 0-0.5 dgerees negative
Caster 3.5 or more degrees positive (if you have manual steering the more you add the harder turning the wheel will be)
Toe 1/16" toe in per side (make sure you start with the centerlink centered in the car, you can't go by the steering wheel placement as it may have been altered at some point)

If you can't find a reputable alignment shop that works on old cars I'd advise learning to do the alignment yourself.  I use the Fastrax system and align all my own vehicles after being continually disappointed in the alignments I got at local shops.  The big chains (NTB, etc.) by and large are not good places to take a classic.  They run on volume not precision.  You want a shop that will align it to the specs you give them, and know how to make the adjustments to a classic mustang.  Unfortunately, like our cars these shops are fewer and fewer each year, as are the alignment techs that understand them.  If considering a local shop get referrals from forum members or local car club guys.  Honestly, if you work on your own car there's no reason not to learn to do your own alignment.  Its really not some black art; it just requires an understanding of what the adjustments are, how to make them, and how what you're doing effects the cars handling. 
 

I have  a little different experience.  I have both the Arning Drop and 1" lowering sprigs.  Handling is great and tire wear is even.  No bump steer either.  It tracks like it is on rails.  However I also have TCP power R&P and their upper a-arms.  Alignment is per your spec.


 

I bought a rebuilt Chockostang box, a roller idler arm from Opentracker, 245/40-18 tires on 18x8 wheels.

TKOPerformance wrote:

Get rid of the lowering springs and do the Shelby/Arning drop.  The problem with lowering springs is that they negatively modify the suspension geometry.  A lowering spring lowers the car by moving the suspension upwards.  This changes the static angle of the upper and lower control arms, as well as the angle and operating arc of the tie rods.  You will likely get bump steer as a result of using lowering springs without some way to correct the tie rod angle (taller tie rod ends, or an adjustable height tie rod end system). 

Then, you still have the issue's that were present in the stock suspension geometry, namely that there is a tremendous amount of camber gain as the suspension cycles.  What this means is that the tire may have a good contact patch sitting static, but as the suspension loads the top of the tire moves outward and the contact patch gets smaller and reduces road grip.  This is the primary reason why these cars plow like a pig through a turn stock (understeer).

The Shelby/Arning drop both corrects the poor suspension geometry and lowers the ride height.  Its all win, with no negatives.  It greatly reduces camber gain, improves positive caster, and keeps the tie rod operating angle stock.  Lowering springs move the suspension up into the body; the Shelby/Arning drop moves the body down onto the suspension.

A performance alignment will be much easier with the Shelby/Arning drop.  Without it you better set up for about 1.5 degrees of negative camber to get any kind of handling, and positive caster adjustment is going to be limited to maybe 2.5-3 degrees.  With the drop you need about 0.5 degrees of negative camber and 3.5 degrees of positive caster is easily achieved (though more is great if you have the adjustment).  I would add 0.25 degree more positive caster to the RH side to account for road crown. 

Alignment specs with the drop:

Camber 0-0.5 dgerees negative
Caster 3.5 or more degrees positive (if you have manual steering the more you add the harder turning the wheel will be)
Toe 1/16" toe in per side (make sure you start with the centerlink centered in the car, you can't go by the steering wheel placement as it may have been altered at some point)

If you can't find a reputable alignment shop that works on old cars I'd advise learning to do the alignment yourself.  I use the Fastrax system and align all my own vehicles after being continually disappointed in the alignments I got at local shops.  The big chains (NTB, etc.) by and large are not good places to take a classic.  They run on volume not precision.  You want a shop that will align it to the specs you give them, and know how to make the adjustments to a classic mustang.  Unfortunately, like our cars these shops are fewer and fewer each year, as are the alignment techs that understand them.  If considering a local shop get referrals from forum members or local car club guys.  Honestly, if you work on your own car there's no reason not to learn to do your own alignment.  Its really not some black art; it just requires an understanding of what the adjustments are, how to make them, and how what you're doing effects the cars handling. 
 

 

Excellent advice!

I was going to create a new thread but this one is recent and will piggy back on it.

We are just finishing the restoration on a '68 coupe and are wondering about the alignment/steering.   We put a Borgenson PS unit on and the car doesn't track naturally down the road like it used to.  It kind of hunts back and forth, not bad but it is noticeable.   We also replaced a lot of front components during the restoration.   The car has Granada front discs and a stock ride height.   I see up above Bullet Bob put these specs:

Caster: 3.5 to 5.0 degree Positive
Camber:  0 to .5 degree Negative
Toe:  1/16 to 1/8" Toe IN

Does that apply to a '68?   After having it aligned twice by a local shop here is where it is currently.   If the above numbers are correct then hopefully that is the issue.

Sorry I have been incredibly busy and just now getting back to this.  

Yes the steering is a little twitchy and it does dart off center.  It's not good at all like the old feeling of manual steering.  It used to track straight before we restored it.  I will look into the kit you mention.   First I want to get the alignment right to see if that will be good enough. 

So if I don't have the drop how much positive caster can I do, and will that help it track straight?   Is positive caster leaning the top forward or backward?   Sorry for the stupid questions.   I'm not looking for any type of performance setup at this point, just a good driver.   My dad said he is going to try to align it since we apparently can't find someone to get it right.

68P51 wrote:

Sorry I have been incredibly busy and just now getting back to this.  

Yes the steering is a little twitchy and it does dart off center.  It's not good at all like the old feeling of manual steering.  It used to track straight before we restored it.  I will look into the kit you mention.   First I want to get the alignment right to see if that will be good enough. 

So if I don't have the drop how much positive caster can I do, and will that help it track straight?   Is positive caster leaning the top forward or backward?   Sorry for the stupid questions.   I'm not looking for any type of performance setup at this point, just a good driver.   My dad said he is going to try to align it since we apparently can't find someone to get it right.

Positive caster is with the top of the spindle leaning to the rear....Upper ball joint vertically behind the lower ball joint.

With everything stock I was able to get 2.5 degrees of POSITIVE caster which should make the car drive decent, however, you likely will not have good "return to center" with only two degrees of caster and the Borgeson steering box.  I presently have 3.75 degrees of Pos caster and with all new components (tight) it will not return to center.  I also have a Borgeson box.

If it really has negative caster that certainly could make it "twitchy", IMO.

BB

What power steering setup do you have?

The Shelby drop will aid tremendously on camber.  On the long bash trips where I have several cars following in my rearview mirror, I am amazed at the amount of negative camber most Mustangs show as they go down the highway.  It appears to be 3 degrees negative or more as the cars are at speed.  (Those of you who just look at your cars in the garage or at a local car show will not experience this, but then, your tires never wear out, either).  Those who drive them on real road trips will notice it.  The cars gain negative camber at highway speeds, which is the exact place where you need your alignment to be working the best for you.  All that said, you should be dialing in a little bit of positive camber or, at the very least, zero camber.  Real world conditions dictate real world numbers.  I prefer to set mine up for zero camber.  The cars actually drive better on the highway if 0.5 to 1.0 positive camber is used.  Again, I prefer mine at zero.

Definitely do the drop first.  You will need 3.5 degree positive caster at a minimum with the Borgeson system.  They state that in their instructions.  Without enough positive caster the front end will have a tendency to wander.  It will also feel "darty" off center, though that is also caused by too much power assist.  I dropped the assist pressure in mine by 300psi and it eliminated the twitchy steering, BUT I already had 3.5 degrees of positive caster in the front end. 

Honestly the drop takes a day at most.  The front end on these cars is absurdly simple.  I didn't even remove the UCAs, just unbolted them and rotated them out of the way withe rotors and calipers still on the spindle.  Longest part of the process was compressing and reinstalling the springs.  Took me about 2 hours per side, or 4 hours total.

do the arning drop it is so worth it and ya cant beat the price. use the performance specs