If you're knee-deep in a classic project or a custom truck build, you've probably spent a fair amount of time looking at mustang ll control arms and trying to figure out which set is actually worth your hard-earned money. It's funny how a car that most people ignored for decades—the 1974-1978 Mustang II—ended up providing the blueprint for the most popular front suspension swap in the history of hot rodding. But here we are, decades later, and the aftermarket is still booming with parts for this specific setup.
The reason everyone uses this design is pretty simple: it's compact, it handles reasonably well, and it gets rid of those bulky shock towers that take up all the engine bay room in older Fords. But if you're still running the original-style stamped steel arms, or if you're trying to piece together a budget kit, there are a few things you really need to know before you start bolting things down.
Why Tubular Arms Beat the Old Stamped Steel
Back in the day, the factory mustang ll control arms were made of stamped steel. They were "fine" for a 100-horsepower commuter car in 1975, but they aren't exactly what you'd call performance parts. They're heavy, they're prone to flexing under load, and honestly, they just don't look that great. When you're showing off a custom engine bay, the last thing you want is a pair of ugly, rusty steel plates holding your spindles in place.
Most guys today go straight for tubular control arms. They're usually made from DOM (Drawn Over Mandrel) steel tubing, which is significantly stronger and lighter. But the benefit isn't just about weight. Tubular arms often have a cleaner design that provides more clearance for steering linkage and headers. If you've ever tried to squeeze a big block into a small frame, you know that every fraction of an inch counts.
Another big plus with modern tubular arms is that many of them are designed with improved geometry. The original Mustang II front end had some quirks, particularly with how the camber changes when the suspension moves up and down. Some of the better aftermarket arms tweak the lengths or the mounting angles slightly to help keep the tire flatter on the ground during a turn. It might not seem like much, but it makes a world of difference in how the car feels on a twisty backroad.
Understanding Narrowed vs. Standard Width
One of the most common questions people ask when shopping for mustang ll control arms is whether they need "narrowed" arms. This is a big deal in the world of custom trucks and slammed street rods.
If you're running wide front tires or you want that "tucked" look where the wheels sit deep inside the fenders, standard-width arms might cause your tires to rub against the fender lips when you turn. Narrowed control arms—usually about 5/8" or 1" shorter per side—pull the wheels inward.
But here's the catch: you can't just swap the arms and call it a day. If you go with narrowed arms, you usually need a shorter rack and pinion (or a narrowed one) to avoid some serious toe-in/toe-out issues as the suspension travels. It's a bit of a "domino effect" situation. If you're building a cruiser with standard offset wheels, stick with the standard width. If you want that aggressive, low-profile stance, narrowed is the way to go, just be prepared for the extra work.
The Debate Over Bushings: Polyurethane vs. Rubber
When you buy a set of mustang ll control arms, they're usually going to come with bushings already pressed in. You've generally got two choices: old-school rubber or modern polyurethane.
Rubber is great if you want a Cadillac ride. It soaks up road vibrations and keeps things quiet. The downside? Rubber is soft. Over time, it cracks and sags. Also, when you're pushing the car hard into a corner, rubber bushings can deflect, which means your alignment is basically changing on the fly. That's not great for predictable handling.
Polyurethane is much stiffer. It holds the control arm exactly where it's supposed to be, which makes the steering feel much "sharper." You'll feel a lot more of the road through the steering wheel. The trade-off is that poly can be squeaky if you don't grease it properly, and it can transmit a bit more road noise into the cabin. Most people in the hobby prefer poly because the performance gain is worth a little bit of extra noise.
Coilovers or Traditional Coil Springs?
The type of mustang ll control arms you buy will also depend on what's holding the car up. There are two main flavors here: arms designed for a traditional coil spring and a separate shock, and arms designed specifically for coilovers.
The traditional setup is what the Mustang II used originally. The coil spring sits in a large "pocket" on the lower control arm. It's a tried-and-true system, and it's generally cheaper. However, adjusting the ride height is a total pain. You usually have to take the spring out and cut a coil off, which is a "guess and check" process that nobody actually enjoys doing.
Coilover-style arms have a flat mounting point or a specific bracket for the bottom of the coilover unit. This is the gold standard for modern builds. You can dial in your ride height exactly where you want it just by turning a nut on the shock body. Plus, it cleans up the look of the front end significantly because you don't have that massive spring pocket hanging down. If you're starting a build from scratch, I'd almost always suggest going the coilover route.
Don't Forget the Ball Joints
It's easy to focus on the metal tubes, but the ball joints are what actually allow your wheels to move and steer. Most mustang ll control arms use standard Chrysler-style screw-in ball joints or the original Ford press-in style.
The screw-in type is really popular in the racing world and with high-end aftermarket manufacturers because they're incredibly easy to replace if they ever wear out. You don't need a massive hydraulic press; you just need the right socket and a long breaker bar. When you're buying arms, check which ball joints they use. Staying with a common, name-brand ball joint (like Moog) ensures that if you're on a road trip and a boot tears or a joint starts knocking, you can actually find a replacement at a local parts store instead of being stranded for a week waiting for a custom part to ship.
Installation Tips and Common Gotchas
So, you've got your new mustang ll control arms on the workbench. Before you start swinging a hammer, there are a few things that can trip you up.
First, make sure your frame is level and square. The Mustang II IFS is very sensitive to how the crossmember is welded in. If your crossmember is slightly crooked, no amount of adjustment in the control arms is going to make the car drive straight.
Second, pay attention to your "anti-dive" geometry. This is the angle of the upper control arm pivots. If they're perfectly parallel to the ground, the front of the car will "nose dive" hard every time you hit the brakes. Most modern crossmembers build in a few degrees of tilt to combat this, but you need to make sure your arms are installed in the right orientation to work with that design.
Lastly, don't tighten your control arm bolts until the car is sitting on the ground under its own weight. This is a classic mistake. If you tighten the bolts while the suspension is hanging in the air, the bushings will be "pre-loaded" once you drop the car. This leads to a harsh ride and will tear up your bushings in no time. Get the car on its wheels, bounce the front end a few times to let things settle, and then torque everything down.
Wrapping It All Up
At the end of the day, picking out mustang ll control arms doesn't have to be a headache. It really comes down to how you plan to use the car. If it's a budget-friendly cruiser, a set of standard-width tubular arms with rubber bushings will do the trick and look a hell of a lot better than the stock stuff. If you're building a pro-touring machine or a show truck, go for the narrowed, coilover-ready arms with poly bushings.
Upgrading your front suspension is one of the best things you can do for the "driveability" of your classic. There's nothing like the feeling of taking an old car that used to wander all over the road and turning it into something that actually goes exactly where you point it. Just take your time, measure twice, and don't cheap out on the components that keep your wheels attached to the car. Your future self—the one driving down the highway at 70 mph—will thank you.