Street or Track Tubular +Caster Upper Arms

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  • $649.00

Tubular +Caster Upper Arms for 65-73 Mustangs.

Sold as a pair.  Includes mounting hardware.


These arms are shipped with 3 degrees of positive caster dialed into the adjustable heim bearings.  More caster is achievable by threading in or out the heim bearings.  Track width can also be adjusted.

For our pivot we use a chromoly, heat treated heim bearing.  Metal to metal support on the ball to body can handle heavy shock & vibration loads and has a increased cross-sectional thickness for greater tensile strength.  This bearing is the big brother version we've used for many, many years of trouble free service in our Adjustable Strut Rods.  Surprisingly this bearing doesn't increase harshness like you would think, instead, it improves the ride quality by transmitting any road irregularities into the shock and spring for those components to soak up the bumps.

This type of bearing not only offers bind free operation, but as an added bonus the threaded section can be used for adjustment to change the length of  both control arms.  By adjusting the length of both control arms for alignment and minimizing the stack of shims used to compensate for chassis variances, a more rigid connection to the shock tower is achieved. 

When combined with a set of our  Tubular Lower Control Arms and a  Lower Control Arm Camber Kit we were able to achieve over -5 degrees camber with the bearing threaded all the way in and the arm bolted straight to the shock tower on our 66 Mustang test car.  We then left the UCA bolted to the tower and used the  Lower Control Arm Camber Kit to pull the LCA in so we could get our track alignment camber setting of -2.75 degrees.  Combined with our  Adjustable Strut Rods we set in +5 degrees of caster.


As well as improving camber gain, a shorter UCA also increases tire clearance.  By using the UCA as short as possible and a  Lower Control Arm Camber Kit to set camber a 245/45/17 tire can be installed up front on our 66 (with a rolled fender lip).  Every car is different however so your results may vary!  To gain even more caster and tire to front fender clearance, the front heim bearing can be un-threaded further than the rear bearing.  This dials in positive caster so the strut rod doesn't have to be as short giving more tire clearance to the front valance if using a large tire.

But I don't have a   Lower Control Arm Camber Kit

We sell them.  Don't want one?  No problem, thread out the heim joint bearing to make each UCA longer, then use a minimal amount of shims to set alignment.  Just make sure both arms are of equal length!  The limitation of this however is you can only make the upper arm as short as it will go.  After this you run out of negative camber adjustment.  Use the  Lower Control Arm Camber Kit for more adjustment.

What if I want a street alignment - something around -0.5 degrees camber?

Easy.  Just thread out the heim bearing an equal amount on each control arm and use shims or the  Lower Control Arm Camber Kit to get the camber setting you want.  Don't want to take the arms off the car?  No problem, just use shims or the  Lower Control Arm Camber Kit.  Complete, detailed instructions, performance and track alignment settings included with the control arms.

Why not use a barrel adjuster to change the arms length?

We didn't want to use a barrel adjuster to change the arms length because having arms at different lengths would mean the pivot points wouldn't be equal side to side.  This would result in different camber curves left and right.  The same issue should be mentioned for setting alignment with barrel adjusters.  By adjusting the length of the arms to get the correct alignment, inevitably you'll end up with different length arms and thus a different camber curve on each side of the vehicle.  This is only beneficial for your alignment guy, not your cars handling.  For anybody that wants a second opinion on keeping both arms equal lengths, read Bob Bolles' 'Stock Car Setup Secrets' - ISBN 1557884013.



By not using a barrel adjuster we were able to use the space they would occupy for a cross brace tube. 

This adds additional stiffness to our UCA's


The images below represent our attention to detail and a competitors lack of it.  On the left is a FEA simulation we ran on our control arms.  It highlights peak loads in the tubes just short of the ball joint plate.  By adding the rear cross brace near the heim bearings we were able to significantly increase the strength of our arms.  The analysis proved that we achieved a 3:1 safety factor, even when using inflated inputs of a 4000lb car braking over 1G and cornering at 1.3G. 

The image on the right shows a competitors bent arm.


We built these control arms with performance and handling in mind.  If that means it takes longer to set the alignment because both UCA's need to be the same length then so be it.  Your lap times or freeway on/off ramp outings will benefit.

Bottom line...

We've developed a rigid, stiff, rebuildable set of control arms that fix the stock control arm positive camber characteristics.  Combined with the large range of possible camber/caster settings these control arms offer something for the weekend street cruiser to the drag or road race Mustang owner.

Specifications & Benefits Short List:

  • Shortened arm and angled ball joint plate increases camber gain.
  • Tubular design makes for a lightweight, rigid structure.
  • .156 Wall seamless tubing.
  • TIG welded construction.
  • Shipped with the front bearing 3 turns further out than the rear.  This adds approx. +3 degrees of positive caster to the spindle when installed before having to shim the front bolt or shorten the strut rod.  More or less is easily possible by simply adjusting the bearings in or out. Our shop '70 Mustang easily runs +7 degrees of caster with our Tubular Lower Arms & Strut Rods.
  • CNC machined, steel/plated cross shafts - no weak aluminum drop shafts for us!
  • Moog ball joints, bearings and all nuts and bolts are replaceable 'off the shelf' components making these arms easily serviceable.
  • Durable powder coated high gloss black finish.
  • UCA accepts stock spring perch or rollerized perches.  No need to drill or weld and re-drill new mounting holes as these are compatible with stock, 1" drop or 1-3/4" drop holes.
  • Includes CNC laser cut steel plate 'Shelby Drop' lowering template (#STUCALDJ6566 or #STUCALDJ6770 depending on year arms purchased).
  • Sold as a pair and shipped fully assembled with detailed installation and alignment instructions.


  • SOT-UCA6566 fits 60-65 Comet, 64-65 Cyclone, 60-65 Falcon, 65-66 Mustang, 60-65 Ranchero,
  • SOT-UCA6773 fits 66-77 Comet, 67-73 Cougar, 66-71 Cyclone, 66-71 Fairlane, 66-70 Falcon, 70-77 Maverick, 68-71 Montego, 67-73 Mustang, 66-71 Ranchero, 68-71 Torino


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Watch this quick YouTube video to understand the benefits of the Shelby Drop and our Dropped Shafts:

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