The 1973 Challenger represents the tail end of the E-body platform, sharing most mechanical DNA with earlier models but saddled with emission controls and detuned engines. The core drivetrain is robust, but 50+ year-old rubber, electrical systems, and body rot are the real killers.
Timing Chain Stretch and Gear Wear
Common · high severityTypical onset: 80,000-120,000 mi or unknown history
Symptoms: Rattling noise on cold start that fades as engine warms, Hard starting or no-start after hot soak, Engine stumbles or backfires through carburetor, Check timing and it's off by 5-10 degrees despite distributor adjustment
Fix: Replace timing chain, gears, and tensioner. LA-series small blocks (318/340/360) are notorious for nylon cam gear teeth shedding. Big blocks less common but still stretch chains. 6-8 hours labor including setting up timing marks, new cover gasket, harmonic balancer removal. DO NOT skip the oil pump inspection while you're in there.
Estimated cost: $800-1,400
Carburetor and Emission System Nightmare
Common · medium severitySymptoms: Hesitation off idle, stumbling under acceleration, Black smoke or flooding after sitting, Vacuum hoses cracked, missing, or incorrectly routed, EGR valve stuck or air injection pump seized
Fix: The 1973 emission controls are a rat's nest—EGR, air pump, thermal switches, and detuned Thermoquad or Carter carbs that nobody remembers how to tune. Most owners rip it all off and retrofit a pre-smog intake/carb setup. Proper restoration: 4-6 hours diagnosing vacuum leaks, rebuilding or replacing carb, new vacuum lines. Many shops won't touch it and recommend conversion to Edelbrock 1406.
Estimated cost: $600-1,200
Torsion Bar and Upper Control Arm Bushings
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Clunking over bumps from front suspension, Wandering steering, vague on-center feel, Uneven tire wear on inside edges, Visible cracking or missing rubber in upper control arm pivot bushings
Fix: Original rubber bushings are long dead on most survivors. Upper control arm bushings require pressing or replacement arms. Torsion bars rarely fail but adjusters seize. Plan on full front suspension refresh: bushings, ball joints, strut rod bushings, alignment. 8-10 hours labor if everything cooperates. Seized adjusters add time.
Estimated cost: $1,200-2,000
Cowl and Torque Box Rust
Common · high severitySymptoms: Water leaking into passenger footwell, Rust bubbling under front fenders near cowl, Soft or cracked metal in frame rail behind front wheels, Sagging or misaligned doors due to flexing structure
Fix: E-bodies trap water at the cowl plenum and drain through torque boxes that rust from inside out. Cosmetic patches are temporary—proper repair requires cutting out rust, welding in patch panels or full torque box replacements. Body-off or major disassembly needed for structural work. 40-80 hours depending on severity. This is the car-killer for Challengers.
Estimated cost: $5,000-15,000
Fuel Tank and Sending Unit Rot
Occasional · medium severitySymptoms: Fuel gauge reads full all the time or bounces erratically, Fuel smell or visible leak at tank seams, Rust flakes in fuel filter after sitting, Hard starting after fill-up due to vented vapor
Fix: Original steel tanks rust internally and externally. Sending units fail from corrosion. Tank replacement requires dropping exhaust and rear axle on some setups. 3-5 hours labor. Strongly recommend replacing fuel lines from tank to pump at same time—original steel lines collapse internally. Sending unit alone is 2 hours if tank is clean.
Estimated cost: $500-1,000
Wiring Harness Deterioration and Bulkhead Connector Meltdown
Occasional · high severitySymptoms: Intermittent no-start, gauges go dead randomly, Smell of burning plastic near firewall, Headlights dim when using wipers or turn signals, Melted or corroded pins visible in bulkhead connector
Fix: The bulkhead connector at the firewall carries all power through undersized terminals that overheat and corrode. Common Mopar problem. Bypass or replace connector, often requires rewiring sections of harness. Dash harness deteriorates too—insulation cracks and shorts. Full diagnosis and repair: 6-12 hours. Complete harness replacement from aftermarket: 20+ hours.
Estimated cost: $800-3,000
Buy one if you're handy with bodywork and patient with carburetors, but walk away from rusty examples—there are cleaner '73s out there that won't need $20k in metal surgery.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.