Free Shipping On Orders Over $49. Details

Talk to a Mustang Enthusiast
M-F 8:30A-11P, Sat-Sun 8:30A-9P
Win $5,000 From Rovos! Enter daily!
Win Any MBRP XP Series Exhaust! Enter Daily

QA1 Adjustable Rear Upper Control Arms (79-04 All, Excluding 99-04 Cobra)

AmericanMuscle no longer carries the QA1 Adjustable Rear Upper Control Arms (79-04 All, Excluding 99-04 Cobra). Please check out Ford Mustang Control Arms for an updated selection.
This item currently can not be added to your cart. Please try again later.

Features, Video & Details

  • Improves Traction
  • Eliminates Wheel Hop
  • Tubular Steel Construction
  • On Car Adjustable
  • Direct Bolt-On Upgrade
  • Sold as a Pair
  • Fits 1979-2004 Mustangs, Excludes IRS Cobra

Review & Installation Video

Review & Install Video

I’m Justin with, and this is our acceleration pack bolt on build up for all 99-04 Mustang GTs. The focus of this pack is of course acceleration, but in order to accelerate faster you need traction, and lots of it. That’s why the majority of the parts used for our build today are focused on getting us off the line much quicker, ultimately resulting in faster acceleration. But before we go over all the parts we have in store for our 2000 GT here, let’s get it out of the shop and do a quick 0-60 baseline run, just to see where we stand now. Alright, before we go installing all of our parts for the acceleration pack, we’re going to do a baseline 0-60 run, using our iTSX wireless tuner and my iPad here, just to see where the car stands now, so hit start and here we go. Alright so it looks like we just clicked off a 6.66 0-60 time with our automatic 2000 GT, which is pretty average for this model car. Now we’re going to take our car back into the shop, talk a little bit more about some of the parts we have in store, and get them installed. Since traction is the theme of the day, what better way to get more of it, than by using a set of these NITTO NT555R Drag Radials, those large tread blocks paired with that real soft compound is going to give us a ton of grip both on the street and at the strip, and should really help our GT get off the line. To further help our GT hook we decided to go with some vital suspension components from QA1, starting with these box style rear lower control arms, these bars are a variation of the classic traction bar design, and basically help keep the rear axle from moving around under load, and especially on hard launches, eliminating any excessive wheel hop. We also decided to go with a set of these QA1 adjustable rear upper control arms, that are fully adjustable while still on the car. These are going to be key to adjusting our pinion angle which is not only important for traction, but also for driveline smoothness. These are really going to help firm up the rear end of the car, and eliminate any side to side sloppiness or wiggle, making the car track a lot straighter, and just making for an overall better driving experience. Moving away from our traction and getting into another big contributing factor to our acceleration, that’s right our gearing. From the factory, our automatic 2000 GT came with 3.27 gears, which is pretty weak for acceleration. That’s where these Ford Racing 4.10 gears come into play, simply put, that shorter gear ratio is going to help our car accelerate faster. Quite frankly, I’m quite anxious to see how it’s going to wake up our 2 valve motor. So now that you know what we have in store for our GT, we’re going to hand the car over to the crew and get everything installed, after they’re all done we’re going to take our GT back out on the street, just to see how it behaves on the road, and to see if we’ve improved on our 0-60 time. Alright so we’re out here on the street with our 2000 GT, we just had the acceleration pack installed by the guys back at the shop, and we’re just cruising, I mean the car is very mild mannered, we’re in overdrive, you’d never be able to tell there’s gears in the car, until you do a little squeeze on the throttle, and man does it go. It goes, it goes, and it hooks hard too. I mean we didn’t even have a chance to heat cycle the tires there and it just dead hooked on the street. Car is a little stiffer in the rear, that’s attributed to the stiffer bushings in both the QA1 lower and upper control arms, but that’s going to be a good thing, that’s going to help keep the car straight, going down the track, it’s also going to reduce our wheel hop as well, and overall just improve our acceleration. So now we’ve had the chance to drive the car around on the street a little bit, see how it reacts in everyday situations, we’re going to put it to the ultimate test, get it back to the shop, do a hard launch, and see if these parts work in lowering our 0-60 time. Alright, so we just finished up our second 0-60 run, and we just clicked off a 5.09 second 0-60, that’s over half a second off our baseline number, so it’s easy to see our acceleration pack is doing its job, and I’ve got to admit, those radials definitely helped us hook on the pavement. So that does it for the acceleration pack, be sure to check out our other 99-04 bolt on build ups where we make our GT handle a bit better, we give it some more power, and dress it up a little bit.

Improves Traction. If you can't "hook up" you are going nowhere fast. That is why QA1 designed their Rear Upper Control Arms to be adjustable so you can dial in your Mustangs suspension to eliminate excessive wheel hop, improve traction, and decrease your 60ft. times.

Tubular Steel Construction. QA1 Rear Upper Control Arms are constructed from 1-1/4" diameter, 0.120" wall steel tubing for light weight and superior strength. Graphite impregnated polyurethane differential bushings are included to replace the soft stock OE rubber bushings.

On Car Adjustable. The QA1 Rear Upper Control Arms are designed to be adjusted without removing the arms from the car. Simply loosen the jam nuts and set the pinion angle as desired for improved traction and better handling.

Application. These QA1 Adjustable Rear Upper Control Arms are designed as a direct bolt-on upgrade for the 1979 to 2004 Mustangs with a solid rear axle, not intended for use on 1999-2004 SVT Cobra's with Independent Rear Suspension (IRS).

MPN# 5255

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (2) Control Arms
  • (2) Two-piece bushings
  • (2) Sleeves
  • (2) Bolts
  • (8) Washers
  • (2) Nuts
Installation Info
Tech Specs

You Might Also Like

Customer Photos (1) Submit Your Photo

View 1 Photo

More Products You Might Like

Questions & Answers (6)

5 Top Rated Questions

I bought my car with adjustable upper control arm, how do I adjust them ?

  • These QA1 Adjustable Rear Upper Control Arms are adjusted bu loosening the two jam nuts, and then turning the center section/body of the control arm to lengthen or shorten the control arm. Other manufacturers may have single adjustable where there is only one end that can turn.

Helpful (0)

Why or why not get adjustable control arms???

  • Adjustable control arms are most commonly used on cars that are extremely lowered, and on drag cars. For cars with extreme drops, adjustable control arms allow you to adjust pinion angle as this will be off with a large drop. For drag cars, this is used to adjust pinion angle, as well as to adjust suspension pre load to 0 or near 0.

Helpful (0)

I was fantasizing about a torque arm then I saw these. It seems these should solve the UCA binding issue. This looks to be a good way to get a large chunk of what the torque arm offers without the hassle. On a scale of one to ten, ten being the torque arm and one being the stock setup, how good are these?

  • The QA1 Adjustable Rear Upper Control Arms (79-04 All; Excludes 99-04 Cobra) are a amazing control arm. QA1 is one of the best brands for suspension mods. You will see a very noticeable difference from the stock set up with these.

Helpful (0)

does this affect rear camber angle at all?

  • Hi, These QA1 Adjustable Rear Upper Control Arms can affect rear camber angle since they are adjustable the angle can be adjusted.

Helpful (0)

how will my car react if tighten all the way,loosen all the way, or neutral?

  • Your car won't reach anyway really, from what i know these adjustable control arms are used for better launches. Like at a track for instance, when u launch your rear end sinks and your front end lifts, when that happens the angle of your driveshaft into your rearend changes. Most people try to set this up so when the front end raises they try to acheive basically a straight line from tranny to diff.

Helpful (0) Show 1 more answer
Post Your Question
1 More Question
are adjustable control arms better than fixed? If yes may you please explain why? 1 answer

Recommended For You

Customer Reviews (4) Write a Review

Overall Rating 4.8

out of 5 stars

Installation Time:Afternoon

  • Handling Improvement 4.75 4.8
  • Fit 4.5 4.5
  • Bang For Your Buck 4.25 4.3

  • 5/5

    Installation Time: Weekend

    January 21, 2014

    Be ready for the install..

    I bought these because I have my 2002 GT lowered approximately 4 inches on Bilstein coil-overs in the front, and than H&R springs with Bilstein shocks in the rear with adjustable lower control arms, and was experiencing some drive line vibration since my angle was thrown off. Also my UCA bushings were making all kinds of racket because they were shot. I embarked on the job thinking it would be a quick in and out procedure. Not quite. The bushings in the axle were a nightmare to remove. I ended up having to take a 3/8's drill bit and having to drill out the bushings until they were nothing but powder on my garage floor, than having to clean out the inner part of their housings with a metal wire drill attachment. Once the bushings were out, the new ones slipped in fairly easy, and adjusting the drive line angle was a breeze. First test drive with the new ones on made the whole project worth it though. Completely transformed the way the car felt. No noise, much more sound feeling, and puts down the grip much more efficiently. These are completely worth the project, just be ready for a full day if not two if your bushings are as difficult as mine were.


    Year: 2002 Submodel: GT Seattle, WA, USA

    Helpful (16)

  • 5/5

    Installation Time: Afternoon

    July 23, 2013

    Adjustable is the way to go!

    I recommend getting these if you have a lowered stang and much more solid then stock uppers.


    Year: 1997 Submodel: Cobra Cedarville, Lawrence Township, NJ 08311, USA

    Helpful (12)

  • 5/5

    Installation Time: Less than 1 Hour

    March 22, 2013

    Get these.

    Very easy to install and oncr the pinion angel is set hard alunches really straighten out!


    Year: 2004 Submodel: Mach 1

    Helpful (13)

  • 4/5

    Installation Time: Afternoon

    March 18, 2013

    qu1 adjustable rear upper control arms

    QA1 sticker in box, but the arm says edlebrock? No big deal.... The old was a pain to remove, old bushings stuck in the mount. These arms being adjustable makes sense, but no direction in how to adjust them, still getting noise (and i replaced lowers too). Seems non adjustable uca's would have worked easy, maybe easier! They have a grease fitting, good idea, look good, lightweight.. Ended up adjusting them about 5 times before pinion angle good and no noise.


    Year: 2004 Submodel: GT PA

    Helpful (17)

Related Mustang Categories