UMI Performance 64-72 GM A-Body Front Upper A-arms Adjustable

When you open the box for the UMI Performance 4056-1-B adjustable upper A-arms, you'll find the pair of A-arms themselves, complete with standard height ball joints already installed. You'll also get a hardware kit (Part # 4003) containing Grade 8 bolts, washers, and nylock nuts for mounting, along with polyurethane bump stops and a travel-limiting bolt. These arms are designed for a range of classic GM A-Body vehicles from 1964 to 1972, including popular models like the Chevrolet Chevelle, Pontiac GTO, and Buick Skylark.

These aren't your average replacement arms. UMI built these for serious performance driving, whether you're hitting the track for Pro-Touring, road racing, auto-x, or just carving corners on the street. The key is the race-quality rod ends, which allow for precise, shim-free adjustment of camber and caster. This means you can dial in your alignment exactly how you want it for better handling and steering response. They've also relocated the ball joint pad to increase caster, which significantly improves stability and steering feel, especially at higher speeds. The cross shaft to ball joint distance is also shortened for improved geometry. The arms themselves are constructed from strong 1.250-inch diameter DOM tubing with a 0.120-inch wall thickness, and the cross shafts are CNC machined from 4130 CrMo steel and zinc plated for durability. They're TIG welded for a solid connection and clean appearance, and the ball joint mounting pad is laser cut for accuracy. UMI includes recommended alignment specs and detailed installation instructions to help you get these dialed in.

It's important to note that these arms must be used with A-Body tall spindles, especially when using standard height ball joints. While shims are often not needed due to the relocated ball joint pad, some applications might still require them. These arms are designed as a direct bolt-in when paired with factory or UMI lower A-arms and tall spindles. UMI Performance designs, tests, and manufactures these arms in Philipsburg, PA, USA.