440-Powered 1973 Plymouth Road Runner

Description

The 1973 Plymouth Road Runner represented a major transition for the model as the muscle‑car era faded. Built on Plymouth’s redesigned B‑body platform, it adopted smoother lines, larger bumpers, and federally mandated 5‑mph impact protection. Despite changing regulations, the Road Runner preserved its performance spirit with available 318ci, 340ci, and 400ci V8 engines, while the mighty 440ci four‑barrel remained an option for buyers seeking classic big‑block power. The ’73 Road Runner maintained athletic handling, unique graphics, and the trademark “beep‑beep” horn, along with the remaining echoes of true muscle‑car performance.

Delivered from the factory with a 340ci V8, this 1973 Road Runner is now powered by a 440ci V8 and mated to a 727 TorqueFlite three-speed automatic transmission. The rear end features a limited-slip differential and is held by Gabriel air shocks, while stopping power is provided by front discs and rear drums. The body is refinished in metallic purple with white graphics, a rear wing, faux hood vents, and chrome-finished bumpers. Inside, a B&M gear selector is mounted between bucket seats reupholstered in black vinyl.

This 440-Powered 1973 Plymouth Road Runner is now offered with various spare parts and a clean Colorado title in the seller’s name.

Highlights

• 440ci V8 reportedly sourced from a 1971 Plymouth

• 727 TorqueFlite three-speed automatic transmission

• Refinished in metallic purple with white graphics

Factory Equipment

• Front disc brakes and rear drums

• Woodgrain dashboard trim

• The chassis number (RM21H3G154344) decodes as:

  • R – Plymouth Belvedere/Satellite

  • M – Medium price class (Road Runner)

  • 21 – Two-door coupe

  • H – 340ci V8

  • 3 – 1973 model year

  • G – St. Louis, Missouri, assembly

  • 154344 – Production sequence

Modifications

• Gabriel HiJackers rear air shocks

• Limited-slip differential

• Rear wing

• 15” painted steel wheels

• Cooper Cobra Radial GT tires measure 235/60 front and 275/60 rear

• Dual-snorkel air cleaner

• Bucket seats reupholstered in black vinyl

• B&M floor-mounted gear selector

• Replacement Road Runner emblems and horn

• Auxiliary gauge pod mounted under the dashboard

• Retro-style stereo with Bluetooth connectivity

Servicing

• The seller reports that the following components were replaced under current ownership:

  • Water pump

  • Radiator and fan

  • Alternator and regulator

  • Distributor, coil, spark plugs, and wires

  • Suspension bushings

  • Ignition switch and door locks

  • Windshield washer tank, lines, and switch knob

  • Battery tray and oil pan gasket

Known Imperfections

• Paint chips and other imperfections in the finish

• Interior trim shows wear and a patched side panel

• Oil leak emanating from the timing cover

• Due for wheel alignment service

Ownership History

The Colorado seller acquired this 1973 Plymouth Road Runner out of Oregon in June 2025.

Included Items

• An assortment of spare parts includes a gear selector with linkage and a center console

Additional Information

• This vehicle currently has a loan, which the seller will pay off to transfer ownership to the winning bidder