Finding Quality Suspension Parts for Your 1974 AMC AMX

Restoring or upgrading a 1974 AMC AMX requires careful attention to suspension components. The 1974 model year was the last for the AMX as a separate model, and parts availability can be tricky. This guide covers what you need to know about front and rear suspension, steering, sway bars, and common upgrades. We'll help you identify original parts, aftermarket replacements, and modifications that improve handling without sacrificing originality.

Front Suspension Basics

The 1974 AMC AMX uses a traditional short-long arm (SLA) front suspension with coil springs and tubular shocks. Key components include upper and lower control arms, coil springs, shock absorbers, ball joints, and tie rod ends. Many parts are shared with other AMC models like the Javelin and Hornet, but some are AMX-specific.

Coil Springs

Front coil springs for the 1974 AMX came in different rates depending on optional equipment like air conditioning or heavy-duty suspension. Stock springs are typically around 400-450 lbs/in. Aftermarket options from companies like Moog or Eaton Detroit Springs offer direct replacements or uprated versions for better handling. When ordering, specify the engine size (usually 304 or 360 cubic inch) and whether the car has A/C. Spring sag is common after 50 years, so replacement is often needed.

Upper and Lower Control Arms

Original control arms are stamped steel with rubber bushings. Replacement bushings are available from Energy Suspension or Moog in polyurethane or rubber. If the arms are worn or bent, replacement assemblies can be found from parts suppliers like RockAuto or AMC-specific vendors. Lower control arms are particularly prone to rust at the spring pocket; inspect carefully. Aftermarket tubular control arms (e.g., from Hotchkis or Global West) reduce unsprung weight and improve geometry, but cost more and may not suit a concours restoration.

Ball Joints and Tie Rods

Ball joints are the same for both upper and lower in many cases. Moog sells greaseable replacements that fit. Tie rod ends are also shared with the Javelin. Center link and idler arm are wear items; idler arm bushings often degrade first. Always replace tie rod ends in pairs and get a professional alignment after any steering or suspension work.

Rear Suspension

The 1974 AMX features a solid rear axle with semi-elliptical leaf springs, tube shocks, and a stabilizer bar on some models. Rear suspension parts are generally easier to find than front, but leaf spring availability depends on the spring rate.

Leaf Springs

Rear leaf springs are the backbone of the AMX’s ride and handling. Original springs had multiple leaves (usually 3-5) with a pronounced arch. Common issues are sagging and broken leaf tips. Replacement springs from suppliers like Eaton Detroit Spring are made to original specifications. You can also order custom spring rates if you plan to lower the car or add power. Some aftermarket companies offer “Super Stock” springs for better traction, but they ride harshly on the street.

Rear Shocks

Rear shocks are tube-style with a stock length of about 14-15 inches. Monroe, KYB, and Bilstein make shocks that fit. For improved handling, gas-charged shocks (KYB Gas-a-Just or Bilstein) are popular. Adjustable shocks are overkill for most street cars. Always match shock valving to the springs and intended use.

Rear Sway Bar

Some 1974 AMX models came with a rear stabilizer bar. If your car doesn't have one, you can add an aftermarket bar from Addco or Hellwig, which connects the axle to the frame. This reduces body roll without a harsh ride. Installation is straightforward with basic tools.

Steering & Sway Bars

Steering system for the 1974 AMX is recirculating ball, with a power steering option common. The steering box is unique to AMC and can wear internally. Rebuild kits exist, but a rebuilt box from a specialist is more reliable. Sway bars up front are also shared with Javelin; aftermarket bars in 1-inch or 1.125-inch diameter are available from Addco, Whiteline, or Hotchkis. Use polyurethane bushings for better response.

Upgrades for Handling

For a daily driver or weekend cruiser, a good upgrade path is: polyurethane bushings in control arms and sway bars, upgraded shocks (Bilstein or KYB), and a larger front sway bar. This preserves a comfortable ride while reducing body roll. Avoid overly stiff springs unless your car is primarily for autocross. If you want to lower the car, drop spindles (e.g., from A-bodies) can be adapted but require custom mods. Most restorers keep stock ride height.

Brake Considerations

Suspension upgrades often go hand-in-hand with brakes. The 1974 AMX originally had front disc and rear drum brakes. Larger rotors are available but require spindle modifications. For street use, a master cylinder upgrade and quality pads are sufficient.

Buying Tips

1. Know your codes: Check the build sheet or VIN to see if your car had heavy-duty suspension, which affects spring rates and sway bar sizes.
2. Sourcing parts: Specialty vendors like Big5 Performance, AMC Performance, and Kennedy American carry many parts. National chains like Advance Auto or AutoZone may list items, but verify fitment before ordering.
3. Used parts: Junkyards and online groups (e.g., The AMC Forum) can be good sources for hard-to-find items like control arms or steering boxes, but inspect for rust and wear.
4. Compatibility: Most 1974 AMX suspension parts fit 1971-1974 Javelin and 1970-1975 AMX. Avoid assuming parts from earlier AMX models (1970-1971) are the same; they have different steering and suspension geometry.
5. Quality vs. price: Moog and Energy Suspension offer reliable aftermarket parts. Avoid no-name brands with thin metal or poor bushings.

Final Recommendation

For a safe and enjoyable 1974 AMC AMX, start with a thorough inspection of all suspension components. Replace worn bushings, ball joints, and tie rods with Moog or equivalent. Install new leaf springs from Eaton if the car sags. Add gas shocks from Bilstein or KYB. If you want improved handling, upgrade to a 1-inch front sway bar and polyurethane bushings. Keep the steering box original but rebuild it if it leaks or wanders. This approach maintains the car's character while making it drive like new. Avoid exotic modifications unless you're building a race car, as parts compatibility and road comfort suffer. Stick with reputable sources and don't cut corners on safety-critical parts.