[Wayne67vert]

I never heard of this until yesterday. What does it do for the ride?

 

[Huskinhano]

You can run a softer spring. The A arm has less leverage to compress it as the body rolls in a turn. Or your stock spring will still ride the same except it'll act as a stiffer spring as the body rolls. The only down side I can possibly see is possibly tire clearance. This is why coil over suspensions are the hot ticket. You're moving the spring close to the tire. This is called "motion ratio".

 

[Opentracker Racing]

I never heard of this until yesterday. What does it do for the ride?

It is a modification I came up with to give better handling on the race tracks to the stock type suspension and still be vintage legal. Like Tom said, it improves the motion ratio and that gives a better ride quality.

The two things you get from a coil over is a lack of bind from the pivot points as they all use rod ends and the improved ratio.

With our roller parts and the perch move, you don't get all the way there but you get close to what you get from a coil over and it cost a lot less. I have moved the perch more than 1" on several cars but that takes a little more work than just drilling new holes. As a rule, the 1" perch move will raise the spring rate by about 125lbs and raise the ride height by about 1/2".

There is no down side to it. In a way it's like the upper arm drop, it's all good and it's free.

The photos are of our template for the perch move and one of our roller upper arms with a track roller perch mounted 1" out.

 

[Wayne67vert]

Sounds like a good improvement.
Does it change the alignment?
Is it ok to drive for everyday use?

 

[Opentracker Racing]

Sounds like a good improvement.
Does it change the alignment?
Is it ok to drive for everyday use?

The increase in ride height does change the alignment slightly. Raising the cars 1/2" toes them in a bit. I've found after moving the perch, one half spin of the adjuster sleeve brings the toe angle back to where it was. If you have the car aligned to factory settings, a fresh alignment with our performance settings is an option.

Tech Information - Opentracker Racing Products

It works good on street cars too. I have it on my daily driver and my wife's '61 Ranchero.

 

[SA70coupe]

John, I have just got notification of my new Opentracker UCA, roller LCA, roller perches etc being shipped.
I planned on rotating the spring perches 180 degrees, to achieve something like the mod, but now I read this, is it feasible for me to mod the new UCA's for an outboard movement?
Will 1/2 inch make a difference, or is 1 inch the better mod (if I can)?
Any bind on the shock, and is there any wedge type mods for the upper shock mounting?

Thanks again for your input

 

[multi68stang]

I pm'd John last Friday on this subject, did the passenger side Sunday & the driver side on Monday (yesterday). The mod didn't take long at all but can't really give any insight on how well the mod did as the rest of the suspension is being fully overhauled & upgraded.

 

[Opentracker Racing]

John, I have just got notification of my new Opentracker UCA, roller LCA, roller perches etc being shipped.
I planned on rotating the spring perches 180 degrees, to achieve something like the mod, but now I read this, is it feasible for me to mod the new UCA's for an outboard movement?
Will 1/2 inch make a difference, or is 1 inch the better mod (if I can)?
Any bind on the shock, and is there any wedge type mods for the upper shock mounting?

Thanks again for your input

This mod can be done to any stock style upper arm. Turning the perch around doesn't change the pivot point so there is no change in motion ratio.

The 1" perch move is better than moving it 1/2". Moving the perch 1/2" will make less of a change in the motion ratio. I know a couple of people who moved the perch 3/4". I'm not sure why they did but it works the same, just not as much gain.

There is little to no bind to the shock with a roller perch. There is always bind with a rubber bushing perch. The upper shock mount pivots so there isn't an issue with that.

 

[Huskinhano]

The reason for perch orientation has to do with how the spring sits. The shaft that bolts to the upper control arm is clocked off angle so the spring sits straight up and down when the UCA is at an angle. This pertains only to stock with rubber bushings. If you have either bronze, poly or roller bearing where it pivots freely, which way it goes in is not an issue. If you install a stock rubber bushing perch in backwards, it's going to pitch the spring out.

 

[SA70coupe]

This mod can be done to any stock style upper arm. Turning the perch around doesn't change the pivot point so there is no change in motion ratio.

The 1" perch move is better than moving it 1/2". Moving the perch 1/2" will make less of a change in the motion ratio. I know a couple of people who moved the perch 3/4". I'm not sure why they did but it works the same, just not as much gain.

There is little to no bind to the shock with a roller perch. There is always bind with a rubber bushing perch. The upper shock mount pivots so there isn't an issue with that.

OK, I will be doing the spring perch mod for the Mach1. I already have the spring perch reversed on my 70, however, that is a bushing perch. I seem to think it kicked out the base of the spring a little. Was told it was an old Shelby trick. Is the spring perch exactly equidistant either side/end? My builder told me the tab side was a bit longer, hence the movement of the spring base outboard. True or not?

 

[SA70coupe]

The reason for perch orientation has to do with how the spring sits. The shaft that bolts to the upper control arm is clocked off angle so the spring sits straight up and down when the UCA is at an angle. This pertains only to stock with rubber bushings. If you have either bronze, poly or roller bearing where it pivots freely, which way it goes in is not an issue. If you install a stock rubber bushing perch in backwards, it's going to pitch the spring out.

How do you mean 'pitch the spring out'?

 

[Huskinhano]

How do you mean 'pitch the spring out'?

Maybe a poor choice of works, it will tilt the spring in outwards making it a little more difficult in getting everything back together.

 

[GT289]

It is a modification I came up with to give better handling on the race tracks to the stock type suspension and still be vintage legal. Like Tom said, it improves the motion ratio and that gives a better ride quality.

You're not really trying to claim you are the originator of motion-ratio altering on
Mustang UCAs?
Come on now.
We used it on the tubular arms and the cheater SCCA "factory arms" we did in the
80's. We even put a set of those arms together in 1993 or so for a customer while
I was there.
And we were not the first folks to do it either. I'm pretty sure Bill Maier was well
versed in that mod and never spoke a word about it back in the 70's.

ex-Global West GM
1991-1995

 

[JeffTepper]

John (Opentracker) was kind enough to lend me his templates a couple of years ago to drill my UCA's for the additional 1" outboard perch mounts. My initial motivation was to gain additional ground clearance for the Super Comp full length headers that I am running. The additional 1/2" in ride height made a big difference when it comes to driveways and speed bumps. Ride comfort was not adversely affected. With the help of the LongAcre Camber gauge (borrowed from Monkeystash), Craig (cmayna) and I were able to set the alignment with ease, once we figured out what the hell we were doing !!

Even factoring in the case of beer, this was a big bang for the buck improvement. Thank's again John (and Ryan and Craig).

 

[SA70coupe]

John (Opentracker) was kind enough to lend me his templates a couple of years ago to drill my UCA's for the additional 1" outboard perch mounts. My initial motivation was to gain additional ground clearance for the Super Comp full length headers that I am running. The additional 1/2" in ride height made a big difference when it comes to driveways and speed bumps. Ride comfort was not adversely affected. With the help of the LongAcre Camber gauge (borrowed from Monkeystash), Craig (cmayna) and I were able to set the alignment with ease, once we figured out what the hell we were doing !!

Even factoring in the case of beer, this was a big bang for the buck improvement. Thank's again John (and Ryan and Craig).

Great story.

What improvement in cornering and body roll did you notice?
Do you still have that modification on your car now? Any wear or noise issues? Any harshness over bumps? Do you have the roller perches with this mod?

 

[JeffTepper]

Great story.

What improvement in cornering and body roll did you notice?
Do you still have that modification on your car now? Any wear or noise issues? Any harshness over bumps? Do you have the roller perches with this mod?

Since I drive my car exclusively on the street, I really have not had an opportunity to compare before and after cornering or body roll. Again, my goal was to increase ground clearance.
No wear, noise issues, or additional harshness. I have been running Opentracker roller perches for several years now, an easy decision after Johnpro recommended the upgrade.

 

[Opentracker Racing]

OK, I will be doing the spring perch mod for the Mach1. I already have the spring perch reversed on my 70, however, that is a bushing perch. I seem to think it kicked out the base of the spring a little. Was told it was an old Shelby trick. Is the spring perch exactly equidistant either side/end? My builder told me the tab side was a bit longer, hence the movement of the spring base outboard. True or not?

The spring sits in the middle of the perch, not off to one side. On the perch body's we work with to make our rollers, the end with the tab is 1/8" shorter than the end with the cut out for the ball joint dome. I've not herd of turning the perch around as a Shelby trick, could be though. I think Shelby used the early Falcon spring perches with the grease-able bronze bushing on the track cars.

 

[HoustonGlock]

How's this change work for the '71-'73 Mustang chassis? Improved like the earlier cars or not really needed ?

 

[Franks68coupe]

How much does this impact the wheels, as far as clearance issues? I've got the Shelby/ Arning drop done with 1" drop springs, but have 17 x 8" sn95 wheels to clear my cobra calipers. Any chance I will have rubbing once everything is back together?

 

[supershifter2]

How's this change work for the '71-'73 Mustang chassis? Improved like the earlier cars or not really needed ?

71-73 has the same uca, lca, strut rods, spindle height, and geomitry as the 68-70 mustangs. all improvements done to the 67-70 will improve the 71-73. i should have put 71-73 shock towers in my 68 torino, it also has the same parts and same geomitry and same spindles as the 68-70 mustang.