Seems that they are getting the kit from Mustangs Plus and it should only be done on 67 and up Mustangs.

 

I suppose if your were track racing the car going whole hog might get you the last little bit out of the car but for street use even the 1" inch drop is not really necessary.

Anymore, it is hard to drive any where without so much traffic you just lope along

 

Global west negative roll kit which I have, has an additional drop than the Shelby drop. Not too significant of measurement. Not to sure about the ball joint to be shimmed, but maybe it does because the negative roll arms I have are designed for the additional drop. I think the guy's name is gt350 or something like that on this forum was a global west employee so he might come on here and give you better details.

 

I'm guessing that the shim would be a beveled shim?

 

Yea, it's a wedge that keeps the ball joint from hitting the limit of it's travel.

 

Sounds like diminishing returns to me.

 

I'm far from an expert on it which is better left to guys like GT289. But until then I'll give my thoughts on it. The 1" drop is not exactly ideal but was the most the UCA could be lowered with the stock UCA not binding and breaking the balljoint. The first thing everyone says about doing the Arning drop is it improves the camber curve, which it does. Years back when I started researching, the 1 3/4" drop was the amount where the camber actually had a negative curve. I'm not claiming that as a fact just how I understood it. It has been done up to 2" as well. IMO from what I have learned about suspension work in general, what the Arning drop does beside improve the camber curve but I think every bit as important if not more so is the roll center. The roll center is where several lines of the control arms intersect and where the car "wants" to pivot on during a turn. It is not the center of gravity. With the stock suspension the roll center is a little below the pavement which makes the car feel top heavy and wants to roll. As you raise the roll center it's like moving your legs apart. It make the car want to stay flatter inherently. The more you raise it, the more stable the car becomes...up to a point. Like everything else it can be too much. From what I understand it will make the car understeer at the extreme as well as suddenly letting go without too much warning and I think could cause a dive condition. Other issues will be with bump steer. The more you change pick up points on the suspension, the more it alters the operation of the steering linkage.

When I finally modified my suspension I stuck with the typical 1" drop. I used Street or Track upper and lower arms. Besides SoT recommended just the 1". My thought were that my car is a street car with purpose built control arms that some one smarter then me spent the time to engineer the system as well as modern rubber. I think for the typical beginner, you should stick with just the 1" drop because you better know and understand how it will effect steering geometry and be able to have the know how on how to get out of any trouble you got yourself into in the first place by altering your suspension. And it will change a lot!

My experience from my car is between lowering the UCA 1" and stock in cut GT spec springs, I would guess it's sitting close to 2" lower now. I am so glad I resisted cutting anything off the coils before installing them! I also installed a camber kit on my car. Running slightly more then 1* neg camber and lowering the UCA that 1", I have a bad enough toe in problem that when I go over a crest in the road and the suspension droops, the tires toe in substantially enough that the tires squeal and the front end stays up until I tap the brakes. This is with stock 66 spindles too.

The good news is I think I know enough that I'm pretty confident that I will resolve it to an acceptable amount. I just need the time to actually do the work. The other good news is normally the car handles awesome and is a blast to drive. I've already made quite an impression on some one. Another tid bit I noticed is that each degree of caster will roughly lower the tie rod end of the spindle to the pavement about .100". In theory at 5* caster a 67-73 spindle will roughly have the same bump steer as a 65-66 car will with stock spindles and stock alignment. I plan on using 72 spindles with a bump steer kit as well as juggle caster and be OK. Yes I realize as I turn the wheels the tie rod arm on the spindle will now follow an arc and change it's relationship to bump steer vs stock. Oh well. Other thoughts of mine is by making the whole tie rod assembly longer by altering it's mounting locations will improve toe changes.

 

They posted some pictures of the shim later. It is a wedge. Pretty heavy one at that. I think he's setting the car up for the track. I was just curious about it.

 

ProMotorsports sells a 1 3/4" kit with a ball joint wedge. They also have a bump steer kit that goes along with it. The 1 inch drop is fine for the street.

 

The numbers Arning used were an optimization for a stock length 65/66
UCA. He recommended a 1-inch drop.
The ideal drop is a bit more but is "best" only when used in conjunction
with an ever so slightly shorter UCA.

I think some of the wedge kits for the stock UCAs were using a 1 3/4"
drop. It's too much really. Although more camber gain is apparent,
it fools with roll center movement. Probably the larger camber gain
may be ok at the track - less suspension movement due to the higher
spring rates but on a street car, due to what usually are softer spring
and shock settings, too much camber gain causes more roll center
movement than you really want.

Global's UCA drop is either 1.5" or 1 3/8"....... both templates were
used, depending upon when the kit was sold. Someone on this
forum said theirs was 1 3/8" fairly recently. My '66 car was put
together in 1985 and the drop was 1.5" at the time.
Their UCAs are "ever so slightly" shorter than stock, motion ratio
is changed, BJ angle changed, etc.

ex-Global West GM
1991-1995

 

You know, something else comes to mind about the Arning drop on 67/68 cars.
The cars are different, 65/66 and 67/68. We all know about the lower arms
being longer and the different shock towers. I'm talking about the actual
difference in math.
Where did that 67/68 drop template come from? I'm thinking it's an extrapolation
of the 65/66 drop numbers that Arning provided to Shelby.
We know the 65 Shelby's all received the drop and the 66's up until mid-production
also received the 1" drop. They then stopped doing it, citing cost reduction
reasons.
My thinking is that it wasn't on the table for the '67 Shelbys, so it would have been
"out of sight, out of mind at Ford."
Where did this 67/68 drop template really come from?
I'm betting it isn't completely correct. There's a lot of subtle differences
between the cars (65/66 and 67/68). The geometry of "what happens when"
is altered by those differences.

Like I said, I have nothing to back it up, but I have my reservations about
slightly altering the 65/66 drop, using that on a 67/68 and calling it a day.

ex-Global West GM
1991-1995

 

Where did this 67/68 drop template really come from?

A similar 1" drop template is shown in the old Boss chassis modification book as a stage 2 modification. The book says all modifications shown in it is developed by Ford engineers or leading indepents in the Ford race world.

 

anything over 1" requires a uca with a different ball joint angle. lowering more then 1" with a stock uca will bind and break the ball joint.

 

Don't forget that Shelby continued to campaign Mustangs through '67 and '68. The one inch drop was still being utilized during the Boss 302 racing program.

 

Lots of good information here. I figured some one would know about this. Hopefully this will help some one out in the future who is interested in doing this.

 

I am interested. I want to lower the front a total of 2" but would like to use some progressive rate coils and I can't find 1" lowering coils that are. I would love to find a kit that doesn't use a wedge for the ball joint rather a new uca but all I see is coil over kits for the 67. My interest has been peaked.

 

The simple solution to that is to lower the UCA 1" for the handling (If you think that lower the car 1" you will be disappointed) and then buy the Scott Drake progressive springs and cut them till the front have the hight you want.

 

I was all hot to do 1" on mine

Until I got behind the suspension.

Some prior owner must have tried 1 3/4" already.

I wasn't about to drill another set of holes so the UCA sit at the stock locations.

 

I was all hot to do 1" on mine

Until I got behind the suspension.

Some prior owner must have tried 1 3/4" already.

I wasn't about to drill another set of holes so the UCA sit at the stock locations.

What did you do in this case? It seems I may be in the same situation.

 

I have the Pro Motorsports kit. Haven't installed it yet. The included steel template is 1 3/4", there are machined wedges to angle the upper ball joint inward so they won't break. Over 1" will break the ball joint according to everything I've read. New Moog joints are included. I also bought their progressive rate fronts. Big difference and worth the cost. I haven't installed yet because I use adjustable StamBar front and rear bars so sway is very limited. If roll is controlled so is the problem. Still, might be fun to experiment.

 

you can lower to much. anything past 1.5" will cause other problems with handling. 1.375" is ideal and has ben proven with much track testing at willowsprings raceway and computer modeling agaist other measurements. you MUST have a uca with the correct ball joint angle so it doesnt bind and break. uca lenght is also important. the 67-70 will give better results due to the longer lca. if i had kept the 65 shock towers i would have used the 67 lca , strut rods and strut rod brackets. the 65-73 uca are the same lenght pivot to pivot cl. i have 69 wrap around shock towers in my 65.

 

the 67-70 will give better results due to the longer lca. if i had kept the 65 shock towers i would have used the 67 lca , strut rods and strut rod brackets.

i've not heard of doing this before, but it makes sense. instead of a shorter aftermarket UCA, you use a longer factory LCA. please tell us more:

- who all has done this before?
- how much modification is necessary on a 65/66 to make the 67 LCA & strut fit?
- i imagine a thick upper spacer/shim will be needed to correct the static camber?
- won't that push your front track out some, and potentially cause tire fit issues with the fender lip? 225 tires already usually need a rolled front fender lip in order to fit.

.

 

For those wondering how much lowering the UCA will have, here's my 66. The UCA is lowered 1" all suspension parts are SoT. The front coils are un cut, stock length GT spec coils also from SoT. I think having no rubber bushings and all roller bearings might have helped lower the car a little bit. I'm not saying every car will sit like mine, rather how mine sits for a reference point. For those wondering about the rear, they're stock sagging 46 YO leafs. The front wheels are pulled forward in the wheel openings due to added caster, 3.5* from adjusting the struts.

 

For those wondering how much lowering the UCA will have, here's my 66. The UCA is lowered 1" all suspension parts are SoT. The front coils are un cut, stock length GT spec coils also from SoT. I think having no rubber bushings and all roller bearings might have helped lower the car a little bit. I'm not saying every car will sit like mine, rather how mine sits for a reference point. For those wondering about the rear, they're stock sagging 46 YO leafs. The front wheels are pulled forward in the wheel openings due to added caster, 3.5* from adjusting the struts.

That's interesting, I measured the fender gap and I had 2" hence why I wanted 2". I think I am just going to do the 1" drop, see how she sits

 

It the holes are already there you can do one of two things, you could use the holes and possibly change out the UCA for one that will work with them, or weld the holes up and re-drill at the 1" mark. Nice thing about steel, it welds up nice so things like this can be fixed.

 

To be clear, Ford engineer Klaus Arning came up with the idea of lowering the Mustang upper control arms 1" to improve suspension geometry. It's not really about lowering the front of the car, although that does help. Shelby had heard about Arning's recommendation and that's where he got the idea to lower the control arms on his GT350 Mustangs.

Arning also designed a multi-link rear suspension for the Mustang. A few prototypes were built. Ford had planned to offer the "independent" rear suspension as a Mustang performance option. Ultimately, the Mustang was selling so well, they didn't need this option to sell more cars. And, in track tests, they discovered most of the handling benefits came from lowering the upper control arms and not from the independent rear suspension. So, neither Ford nor Shelby ever bothered with Arning's rear suspension mods. (Ford did use Arning's suspension design for the GT-40).

Early Mustang racers lowered the upper control arms 1.5" or more. They started breaking ball joints. This is why some people, to this day, say you shouldn't lower the upper control arms or you'll break ball joints. They missed the fact that the ball joints break only if the control arms are dropped more than 1". As mentioned, doing this requires wedges for the ball joints.

Lowering the upper control arms more than 1" is indeed a case of diminishing returns. For the vast majority of Mustangs, 1" is fine and results in a significant boost in handling performance. Anything more helps only a little. So, it can be worthwhile for a dedicated track car, but not for most street cars.

 

I went through all of this a few years ago when I built my Shelby clone. I decided to go with the 1.75" drop because I kept reading over and over again that the 1" wasn't ideal, it was just as far as you could go with the stock UCA's. After doing some research I found that there were a number of aftermarket control arms that basically corrected the balljoint angle but realistically did little else. I wanted my car to LOOK 100% stock so that idea was out. A member here (opentracker) offered roller spring perches and modified factory UCA's so I decided to modify my own. I cut and split the balljoint mount and made the correct adjustment and then re-welded and reinforced and boxed my UCA's. I also boxed the LCA's. I also went with a 1" lower spring. They looked great, worked great and he car handled exactly the way I wanted it to.

 

Do you have a pic of how it sits now and what year?