Before purchase, every Speedtech Chassis configuration is reviewed by our team to confirm fitment, performance goals, and upgrade compatibility.
Create your build to receive expert validation and final pricing, or share your build goals with a Speedtech specialist to get a custom recommendation.
Upgrade your ’68–’72 GM A-body Chevelle or GTO to the ultimate in performance, comfort, and drivability with the Speedtech Performance ExtReme Full Chassis featuring Independent Rear Suspension (IRS). Built for no-compromise handling, this system excels on the street, dominates autocross, and thrives on the track.
Optimized suspension geometry, forged aluminum spindles, and clearance for up to 315mm front tires ensure every aspect is engineered for real-world performance. And the Independent Rear Suspension giving you all of the rear end compliance, strength and tuning ability you could over need. 
AGGRESSIVE STANCE, WIDE TIRE FITMENT
Designed with wide wheel and tire combos in mind, this subframe accommodates up to a 315/30/18 tire with full steering clearance. High-clearance control arms and optimized geometry let you slam the car for that strong pro-touring look without compromising performance or drivability.
PRECISION STEERING FEEL, DUAL RACK PERFORMANCE
At the heart of this system is a dual power rack and pinion from Sweet Mfg., giving you a quicker ratio and improved feedback for confident cornering. Combined with our billet steering arm and ExtReme spindle geometry, you’ll feel in full control at every turn.
RACE-BRED STRENGTH, STREET-READY RELIABILITY
Box-welded construction with tabbed-through gusseting maximizes torsional rigidity, while our 7075 forged aluminum spindles bring lightweight strength to the front end. It’s engineered to take abuse—on and off the track.
INDEPENDENT REAR SUSPENSION
Speedtech Performance’s ExtReme IRS system is not just an upgrade; it's a complete transformation of your classic car's handling capabilities. By incorporating advanced suspension technology, it delivers a modern driving experience while preserving the timeless appeal of your vintage vehicle.
MADE IN THE USA WITH PRIDE
Every Speedtech subframe is built right here in the USA, using premium materials and expert craftsmanship. We believe in building it right the first time—with no compromises.
INSTALLATION MADE EASY, NO GUESSWORK
The ExtReme Chassis bolts directly to the stock location, making installation straightforward for builders, pros, or advanced DIYers. To achieve the proper driveline angle, floor and tunnel modification will need to be done. However, Speedtech offers a full transmission tunnel, driveline and axle tunnel kit. This teamed up with our IRS closeout sheet metal, all of the material is ready for you!
