Product Summary

Front Position, Mustang II Crossmember Type, Steel

  • This IFS crossmember is a great way to improve your vehicle's suspension, handling, and overall performance
  • Works with both manual and power rack and pinions
  • 1955-1959 Chevy Truck
  • Can be used with stock stamped style control arms or tubular control arms
  • Choose from a variety of front suspension kits to finish off your front end

Key Specs

MFG. Part #91034429-DLX
Crossmember TypeMustang II
Crossmember StyleBoxed
Attachment StyleWeld-on

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Speedway Motors 91034429-DLX Details

  • Vastly improved handling when compared to original suspension
  • Front steer rack-and-pinion steering provides greater steering feel
  • Complete weld-in assembly made from 3/16-inch steel adds strength
  • Vertical inner uprights provide a strong design with twice the weld area
  • Application specific crossmember and spring towers pre-welded to save installation time
  • Allows for numerous control arm and disc brake kit upgrade options
  • Compatible with manual or power rack-and-pinion steering systems
  • Compatible with stock stamped steel control arms as well as tubular control arms
  • Stock style control arms will require strut rod brackets or tubular strut rod kit
  • Rack-and-pinion mounting points rotated rearward 20 degrees for steering shaft clearance
  • Built-in anti-dive and bump steer correction mounting points
  • Lower control arm pivot tubes and corner gussets not included
  • Accepts stock Mustang II spindles or aftermarket drop spindles
  • All welds ground smooth, saving you time and energy during installation
  • Works with both 1/2 ton 3100 chassis as well as 3/4 ton 3600 chassis frames

Drastically Improve Your ’55-’59 Chevy Truck’s Handling with A Mustang II IFS Crossmember

Much like the advent of hydraulic, or “juice” brakes, became an industry standard, so has independent front suspension (IFS). You’ll find IFS on just about every production car and light duty truck sold in America due to its inherent improvement in ride quality, handling, and the ability to provide better control at higher road speeds. These updates are what can turn a long drive at highway speed in your ’55-’59 Chevy truck hot rod from sketchy to serene simply by replacing the outdated straight axle suspension and its kingpins and dual leaf springs for a well-engineered weld-in IFS solution utilizing the tried and true suspension geometry that debuted on the 1974 Mustang II.

Built Strong to Handle the Road Ahead and Look Good Doing It

Like most trucks built in this time, they were designed for hauling and not personal or recreational use like we enjoy our trucks today. To that end, GM opted for the frugal, yet strong straight beam front axle suspended by a leaf spring at each side. Great for the rutted dirt roads going from the farm into town carrying crops, but terrible for today’s road manners and speeds. On top of that you’re limited in spring rate and shock choices for modern handling and the steering linkage setup with bushed kingpins creates some hair raising steering feel, or lack thereof, when you get up to highway speed. Of course, there is always the effect of alignment on a front suspension and getting a straight axle front end aligned is no small chore, often requiring heating/bending of the axle tube itself or other modifications.

Converting your ’55-’59 Chevy truck’s chassis to the Mustang II front suspension design with our crossmember kit brings you a whole different driving experience, one that will have you looking for any excuse to get out on the open road and take long trips to events you never attended before due to your Chevy truck’s poor handling at modern highway speeds. Beginning with our 7 gauge steel (that’s a full 3/16 of an inch thick) boxed Mustang 2 front suspension crossmember that is fully welded with extended vertical uprights we have designed in anti-dive geometry to our crossmember and spring towers. Suspension travel, which yields a better ride, is upwards of five inches with our IFS and aligning the IFS can be handled easily by any competent alignment shop. Rack-and-pinion steering provides a quick and crisp steering effort at any road speed, and we have designed our rack mounting tabs to not only be optimized to eliminate bump steer but lay the steering rack back at a 20 degree angle to facilitate a lower steering shaft angle. This helps with exhaust manifold/header and overall engine clearance. The mounts accept both 15-1/2-inch and 16-inch on center rack mount spacing for use with manual or power steering assemblies. Stock height Mustang II spindles will result in a typical 3-4-inch drop in ride height.

Lastly, upgrading to a weld-in IFS Mustang 2 front end kit greatly enhances your braking options with the ability to run the most basic disc brake package all the way up to serious multi-piston racing disc brakes. Track width is dependent upon the brake package you choose, usually adding up to 2-inches to the IFS, creating a 60-inch to 62-inch hub-to-hub width. We do offer 5/8-inch narrower upper and lower control arms if you need the clearance for larger wheel offsets or widths. Additionally, due to the wider truck frame dimensions, 2-inch inner tie rod extensions are necessary. As you can see, our crossmember is the perfect foundation for building the best Mustang II front suspension for your ’55-’59 Chevy truck.

Welds to Your Stock Frame Rails for Strength and Accuracy

We understand that bolt-in suspension upgrades are easier for those that like to spin their own wrenches, but we designed our Mustang II crossmembers to be a weld-in solution to maintain their strength and integrity throughout the life of your ’55-’59 Chevy truck. While we do encourage the use of a certified welder or chassis shop for installation, if you know your way around a measuring tape and have a MIG welder in your garage there’s really nothing stopping you from following our detailed instructions to fit and weld our Mustang II front suspension crossmember into your ’55-’59 Chevy truck’s frame rails.

Welding our Mustang II suspension crossmember into place is a straightforward installation and can be handled in just a few short hours once the old straight axle and front suspension have been removed. If you are going to use stock-style lower Mustang 2 control arms you will need strut rod brackets or our tubular strut rod kit for installation. Note, lower control arm pivot tubes and gussets are not included, as they are typically included with tubular style lower control arm kits. We offer Mustang II control arm kits with and without disc brakes to help you complete your installation. We highly recommend our ’55-’59 Chevy truck part # 91054429 frame boxing plates for increased frame support and strength as well. Lastly, if using a power rack-and-pinion steering unit you will need our rack spacers for proper clearance along with the corresponding longer bolts.


Speedway Motors 91034429-DLX Specifications

MFG. Part #91034429-DLX
BrandSpeedway Motors
Crossmember TypeMustang II
Crossmember StyleBoxed
Attachment StyleWeld-on
Steering System CompatibilityManual/Power Rack and Pinion
Control Arm CompatibilityTubular or Stock
Tie Rod Extensions RequiredYes
Material TypeSteel
Material Gauge7-gauge
Ride Height (w/Stock Spindles)3" to 4" Lowered
Material Thickness0.18"
Sold in QuantityKit
NotesIncludes crossmember and shock cups.