How to Improve Driving Performance on the 1964-1972 GM A-Body Platform
The GM A-Body platform, which encompassed iconic cars like the Chevrolet Chevelle, Buick Skylark, Oldsmobile Cutlass and Pontiac GTO, holds a special place in the hearts of muscle car enthusiasts. These vintage classics boast timeless styling and impressive results in motorsports.
With the embracing of Pro Touring and autocross competition, A-body owners are improving their cars’ handling characteristics to match modern standards. In this guide, we’ll explore how to upgrade the handling of these iconic muscle cars.
This article is an introduction, as modifications can go way beyond anything listed here, from a complete replacement chassis with an independent rear suspension to costly pro-built motors and $10,000 a pair coilovers. We aim to keep it real and within a budget to get A-body owners to experience the fun and camaraderie of an autocross or track day event.
Chassis Reinforcement
H-3 Chassis reinforcement is the backbone of any handling improvement project for your GM A-Body. This process enhances structural integrity and provides a solid foundation for suspension upgrades. As outlined in a Chevy DIY article, one of the essential methods is adding subframe connectors. These connectors tie the front and rear subframes, reducing chassis flex and providing a solid basis for other modifications that improve handling.
Suspension Upgrades
Lowering an A-Body
Muscle cars like the Chevelle and GTO can benefit from front suspension kits that drop the vehicle. A popular option is coilover suspension systems, which offer adjustable ride height and damping settings. Aldan American offers front suspension lowering kits for 1964-1967 and 1968-1972 A-bodies. These kits include either single adjustable coilovers or double adjustable coilovers and POL upper and lower tubular control arms that are lighter and stronger than OEM. The kit allows for up to 2.0 inches of ride height adjustment. Aldan American has a coilover conversion kit regardless of which A-body you own. These kits are 100% bolt-on, with no drilling, cutting or welding required for installation.
Regardless of which GM A-body you own, an Aldan American coilover conversion kit is 100% bolt-on, with no drilling, cutting or welding required for installation. Here’s an article covering a complete A-body coilover conversion.
Here’s an article covering a complete A-body coilover conversion, or check out the video below.
Performance Shocks and Struts
High-quality shocks and struts improve ride quality, reduce body roll, and enhance cornering performance.
Aldan American offers both coilovers and shock absorbers for the GM A-Body chassis.
Aldan American shocks are offered with single or double-adjustable valving for improved ride quality and handling. GM A-body owners can choose from single-adjustable TruLine (with 11-position rebound adjustment) and double-adjustable TrackLine shocks with 66 unique settings.
Aldan American shocks are offered with single or double-adjustable valving for improved ride quality and handling. GM A-body owners can choose from single-adjustable TruLine (with 11-position rebound adjustment) and double-adjustable TrackLine shocks with 66 unique settings.
Performance Coilovers
Bolt-on coilover kits for the GM A-body platform from Aldan American are offered in single or double adjustable valving as well. GM A-body owners can choose from single-adjustable Road Comp Series kits (with 6-11 positions of adjustment) and double-adjustable Track Comp Series kits shocks with 180 unique setting of independent rebound and compression coilover adjustment.
For example, Aldan adjustable coilovers allow you to tune your El Camino’s ride to your preferences. Designed with adjustable spring perches, Aldan equipped ride heights can be lowered by up to 2.0 inches.
Aldan American shocks and coilovers are manufactured from lightweight, high-strength 6061-T6 billet aluminum here in the U.S.A. We choose aluminum over steel for several reasons, including lightness and aluminum’s far better ability to shed the heat generated by the shock’s movements than steel. Aldan Shocks are fully rebuildable and serviceable and are covered by our 100% Satisfaction Guarantee and Limited Lifetime Warranty.
High-strength Bushings
The suspension bushings in vintage GM A-body cars have typically seen better days. Even newer rubber replacement bushings aren’t up to autocross or track day abuse. High-strength polymer replacements significantly upgrade handling by reducing distortion and improving precision in steering and handling. Upgrading to polyurethane bushings and mounts in the control arms, sway bars, and rear suspension components provides more responsive handling, ensuring power is transferred to the wheels efficiently and overall saftey. All Aldan American coilover kits and coilover conversion kits include polyurethane or Delrin® bushings where applicable.
Sway Bars
Roll bars, sway bars or anti-sway bars are one and the same, whose function is to reduce body roll during cornering, keeping your GM A-body level and planted. A larger than OEM front and adjustable rear sway bar is a setup we recommend to help fine-tune your car’s handling characteristics, improving cornering performance and making it more responsive and predictable.
Braking System Enhancements
Upgrading the suspension is vital, but enhancing the braking system is essential to ensure your A-Body can handle high-performance driving without compromise. Let’s address several aspects of the braking system:
Brake Pads
Invest in high-performance brake pads designed for spirited driving. High-performance Chevelle brake pads for OEM calipers are available from Hawk, EBC, Wilwood, and Power Stop. All offer customer support to assist you in making the best selection for your type of use. And if you’re running rear drums, high-perf shoes are available from EBC, Ecklers and Porterfield. We don’t recommend using front drum brakes in critical applications like autocross and track days.
Brake Fluid
Along with brake pads, brake fluid is the most crucial first upgrade to any braking system used in a high-performance application. Both pads and fluid can fade, resulting in a soft pedal and longer stopping distances. A more thorough discussion on brake fade and how to cure it is available at Grassroots Motorsports.
Brake Rotors
Select high-quality brake rotors for your conversion. Slotted or drilled rotors improve heat dissipation, reducing the risk of brake fade during spirited driving, Performance Online (POL) is a company we recommend frequently.
Disc Brake Calipers
Front and rear disc brake conversion kits, with upgraded calipers and larger rotors, provide better brake force distribution and are readily available for GM A-body vehicles. These can range from mixing and matching components from newer GM cars to a Wilwood Classic Dynalite kit with four-piston calipers and 11-inch rotors for less than a grand. The kits are relatively easy to install and can be fitted simultaneously with a front suspension coilover conversion kit and lowering spindles.
Wheel and Tire Upgrades
The wheels and tires you choose can significantly affect your A-Body’s handling performance. Wider, stickier tires provide more grip and traction, while lightweight wheels reduce unsprung weight for improved handling. When upgrading, consider the following:
Tire Selection
It’s best to upgrade to tires that stand the punishment to get the most from your GM A-body in an autocross or track event. After all, all acceleration, braking, cornering and steering forces must be fed through those four contact patches of rubber on the road.
The best all-around choice for use on track and the street is the new generation of 200 UTQG-rated tires. They offer decent street manners with tread compounds, constructions and tread designs that can take the punishment. These high-performing tires are available from BF Goodrich, Bridgestone, Goodyear, Kumho, Yokohama and others. For the SuperChevy Muscle Car Challenge, Aldan American sponsored a 1968 Chevelle running Falken Azenis RT615K+ 315/30ZR18 rear and 275/35ZR18 front.
Wheel Selection
Wheels are an essential factor to consider; it goes way beyond appearance alone. It would be best to consider lightweight alloy wheels to get the most out of the wheel and tire assembly. Lightweight wheels reduce unsprung weight, which results in improved handling and more responsive steering.
Several wheel constructions are available and selected matched to the level of preparation of your A-body and the degree of stress you’re feeding into the tire/wheel/suspension. Cast wheels can look great and provide lightweight but may not be up to heavy-duty use. If budget limits you to cast wheels, look for those formed through high-pressure casting.
More robust still are flow-formed wheels, comprising a cast center section with a rolled rim section. The strongest yet are forged wheels, single or multiple pieces. Forged wheels are used exclusively in professional motorsports. HRBB (Hot Rods by Boyd) has a good selection of custom wheels.
Alignment and Camber Adjustment
A proper alignment, which includes camber, caster, and toe adjustments, ensures that your upgraded suspension and wheel/tire setup work harmoniously. A performance alignment is essential for achieving optimal handling and tire wear. The best advice on suspension setting will come from the track. Ask other A-body drivers what they’re running, especially the most successful ones.
Steering Enhancements
To complete the handling package for your GM A-Body, consider the following steering upgrades:
Power Steering Conversion
Consider a conversion if your GM A-Body doesn’t already have power steering. Power steering makes maneuvering your upgraded car more manageable and enjoyable, especially when dealing with a lower ride height and wider tires.
Steering Box Upgrade
An upgrade to a quick-ratio steering box improves steering responsiveness. It reduces the number of turns needed to go from lock to lock, which provides a more direct and engaging driving experience.
Rack and Pinion
For the most precise steering, consider a rack and pinion upgrade. The cost is comparable to replacing the steering box and all linkages.
Wrapping it Up
Upgrading the chassis and suspension of your 1964-1972 GM A-Body car is a rewarding project that can transform a classic cruiser into a cone-carving Pro Tourer. The steps outlined in this guide, inspired by the Chevy DIY article and enriched with insights from other sources, can help you achieve better handling, responsiveness, and overall driving enjoyment.
From chassis reinforcement to suspension upgrades, braking improvements, wheel and tire enhancements, and steering upgrades, these modifications can make your GM A-Body car a thrilling and capable performer on the road or track. With careful planning and attention to detail, your classic GM A-Body can deliver a driving experience that combines the best of both worlds – timeless style and modern handling.
