1973 · Plymouth · United States
A Name Kept Alive by One Option
For 1973 the GTX name survived only through the Road Runner's optional 440 four-barrel, which came with TorqueFlite only; Mueller's Muscle Car Source Book counts 749 of them.
United States · researched through 2026-09-22
For 1973 the GTX name survived only through the Road Runner's optional 440 four-barrel, rated 280 hp SAE net at 4,800 rpm and 380 lb-ft at 3,200 rpm; Chrysler's own 1973 AMA specifications and Plymouth's data book list no GTX model at all, showing the 440 as an option for the Road Runner coupe, body code RM21, exclusively. That 440 came only with the TorqueFlite automatic, with no manual-transmission pairing documented in either the data book or the AMA specification sheet, and its compression ratio is listed at 8.2:1, the same dual-snorkel single four-barrel configuration carried in the data book's own specifications table.1
Mueller's Muscle Car Source Book counts 749 Road Runners with the 440 package inside a Road Runner hardtop total of 19,056, but as with the figure's own production notes state, no Chrysler build record or registry count was found to confirm the 749, and Mueller names no underlying source of its own. No GTX-package price was located in the sources consulted, leaving the prices section of this record empty for the year, and no transmission split accompanies Mueller's count beyond the blanket automatic-only requirement documented separately in the data book.2
Two further claims were found but not tabulated. Secondary enthusiast sites describe 1972-1974 Road Runners ordered with the 440 as "Road Runner GTX," a naming convention this record notes without adopting as an official Chrysler designation, since no factory document seen for 1973 uses that combined name. A commercial reference site separately states the 749-unit count came entirely with automatic transmission, which would be consistent with the 440's documented automatic-only requirement, but since that site cites no factory record of its own, this record carries the claim as an unpublished lead rather than restating it as confirmed alongside Mueller's 749.2
A Performance Axle Package, restricted to the Road Runner, bundled a Sure-Grip 3.55 axle, a seven-blade torque-drive fan, a 26-inch high-performance radiator with shroud, and a coolant reserve system into a single order. Air conditioning required power steering when paired with the 440, and power front discs were themselves required equipment with that engine rather than an optional upgrade buyers could decline. No prices for any of these three items were found in the sources consulted, so the options section of this record carries their content and restrictions without a dollar figure attached to any of them, a gap that leaves the total cost of ordering a 440-equipped Road Runner for 1973 undocumented in this record.
Fourteen exterior colors were charted for the Satellite line the Road Runner belonged to, from Silver Frost Metallic and Blue Sky through Tahitian Gold Metallic and Formal Black, alongside a halo-style vinyl roof offered in parchment, white, black, green, or gold depending on the exterior color and interior trim combination. Interior trim ran to all-vinyl bench seats standard on the Road Runner in blue, green, or black, with a split-back bench or bucket seats available in five additional colors under the Interior Decor Package. The 1973 AMA body-model table carries no separate GTX code, listing only RM21 for the Road Runner coupe that the 440 option rode on.1
Fact sheet · 1973 · United States
The numbers
1973 Plymouth GTX (Road Runner era) — For 1973 the GTX name survived only through the Road Runner's optional 440 four-barrel, which came with TorqueFlite only; Mueller's Muscle Car Source Book counts 749 of them.
Coverage: Partial — researched sections are shown; missing ones are not yet sourced. Researched through 2026-09-22.
Every figure is labeled with how sure we are. Reported means a manufacturer, registry, or reference figure we cite but have not reconciled against factory records ourselves. Disputed means credible sources disagree and both are shown. Rows are separately scoped; don't add them together unless the note says they make up a total.
Production
| What was counted | Count | Basis | Status |
|---|---|---|---|
| Road Runner with GTX 440 package2 Road Runner GTX (440 package) · 2-door hardtop · 440 4-barrel V-8 · not stated Mueller counts these inside the Road Runner hardtop total of 19,056; the Road Runner year record carries that total. No transmission split is given by this source. | 749 | not stated (reference-book production table), model-year | Reported |
No Chrysler record was found for 1973 GTX production, and no GTX package price was found; the production row comes from Mueller's Muscle Car Source Book. Engines, paint and trim come from Plymouth's 1973 dealer literature for the Road Runner host model; the Road Runner year record carries the host-model production figures.
Mueller's Muscle Car Source Book (2015) gives 749 Road Runners with the GTX 440 package for 1973, inside its Road Runner total. A whole-year GTX figure cannot be stated separately from the Road Runner total (searched 2026-09-29; no source prints one). It names no Chrysler record, so the figure is reported, not verified; a Chrysler build-record count or the Galen Govier Mopar registry would confirm it.
Engines
| Engine | Factory rating | Availability | Built |
|---|---|---|---|
| 440 4-bbl V-8 (dual snorkel)1 440 cu in · single 4-barrel | 280 hp @ 4,800, 380 lb-ft @ 3,200 (SAE net) | optional on Road Runner only; automatic only | Not yet sourced |
Ratings are the manufacturer's advertised figures under the standard shown (SAE gross before 1972, SAE net after). They are not dyno results, and gross and net ratings can't be compared directly.
Transmissions
| Transmission | Availability | Built |
|---|---|---|
| TorqueFlite automatic1 | required with the 440 | Not yet sourced |
Options and packages
| Code | Option | Price | Installed |
|---|---|---|---|
A36package |
Performance Axle Package (Road Runner only) | — | Not yet sourced |
|
Air conditioning (power steering required with 440) | — | Not yet sourced |
|
Power front disc brakes (required with 440) | — | Not yet sourced |
Paint
| Code | Color | Built |
|---|---|---|
JA5 |
Silver Frost Metallic3 | Not yet sourced |
HB1 |
Blue Sky3 | Not yet sourced |
TB3 |
Basin Street Blue3 | Not yet sourced |
GB5 |
True Blue Metallic3 | Not yet sourced |
FE5 |
Rallye Red3 | Not yet sourced |
JF1 |
Mist Green3 | Not yet sourced |
GF3 |
Amber Sherwood Metallic3 | Not yet sourced |
JF8 |
Forest Green Metallic3 | Not yet sourced |
GK6 |
Autumn Bronze Metallic3 | Not yet sourced |
HL4 |
Sahara Beige3 | Not yet sourced |
EW1 |
Spinnaker White3 | Not yet sourced |
TX9 |
Formal Black3 | Not yet sourced |
FY1 |
Lemon Twist3 | Not yet sourced |
JY3 |
Honey Gold3 | Not yet sourced |
JY6 |
Golden Haze Metallic3 | Not yet sourced |
JY9 |
Tahitian Gold Metallic3 | Not yet sourced |
V1L / V1W / V1X / V1F / V1Y |
Halo-style vinyl roof (2-door): parchment / white / black / green / gold; availability depends on exterior and trim colour | Not yet sourced |
Color names are the factory's. We don't show color swatches, because a screen color is no guide for a restoration.
Interiors
| Code | Trim | Built |
|---|---|---|
B2B5 / B2F6 / B2X9 |
All-vinyl bench seat, standard on Road Runner (and Satellite coupe): blue, green, black | Not yet sourced |
C2B5 / C2F6 / C2Y4 / C2X9 / C2L3 |
All-vinyl split-back bench seat, Road Runner with Interior Decor Package: blue, green, gold, black, parchment | Not yet sourced |
D6B5 / D6F6 / D6L3 / D6X9 / D6Y4 / D6XW |
All-vinyl bucket seats, Road Runner with Interior Decor Package: blue, green, parchment, black, gold, white | Not yet sourced |
Identification
- Body code
- RM21 = Road Runner two-door coupe; the 1973 AMA body-model table has no separate GTX code.1
Identification
Read a 1973 Plymouth VIN
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Same model year
Also in 1973
- AMC AMX The Javelin AMX's best year. 5,707 were built, a quarter of them with the 401, alongside the Trans Am Victory decal and the Pierre Cardin interior.
- AMC Gremlin X and Spirit AMX The V8 Gremlin X continued, with new stripes and an available Levi's denim-look interior. No production split has been found.
- AMC Javelin The SST name dropped away and new twin 'TV-screen' taillights arrived. Javelin production reached 25,195, alongside the Trans Am Victory decal package.
- Buick Riviera Stage One (260 hp net) joined a separate GS handling package; 1,234 Stage Ones and 3,933 GS cars of 34,080.
- Buick Skylark Gran Sport, GS and GSX On the new Colonnade A-body the GS became a Century Gran Sport package; 6,637 were built, 728 with the 455 Stage 1.
- Chevrolet Chevelle and Malibu SS The Colonnade Chevelle's only SS year: RPO Z15 on the Malibu coupe and, for the first and only time, the station wagon, with a 245 net hp 454 available.
- Chevrolet Chevy II and Nova Hatchback appears in the source body table; SS offered with any engine per the source. Enthusiast-compiled production: 369,509 cars; Super Sport 35,542.
- Chevrolet El Camino SS The new Colonnade El Camino could still be ordered with RPO Z15 SS equipment; no El Camino SS count was found.
- Dodge Challenger The six was gone: every 1973 Challenger hardtop had a V8, the 318 standard and the 340 optional, with the Rallye now sold as a package.
- Dodge Charger The Charger's best-selling year of the original era, 119,318 cars, came as the 440 lost its Magnum name and the car moved toward personal luxury.
- Dodge Dart GTS, Swinger and Demon Renamed Dart Sport, the fastback's 340 model sold 11,315 in the 340's final year.
- Ford Maverick Grabber The 200 six became standard as the 170 was dropped; Classic Industries counts 32,350 Grabbers.
- Ford Ranchero GT The Ranchero GT continued on the 1972-76 Ranchero; 15,320 GTs were built, per reference-site counts in the Standard Catalog lineage.
- Ford Thunderbird The 429 4V was standard and the 460 4V optional in the sixth generation's best-selling year.
- Ford Torino The 1973 Torino kept the 1972 body behind a heavier bumper; the Gran Torino Sport fell to 51,853 SportsRoofs and 17,090 hardtops while the 351 Cobra Jet remained the performance engine.
- Mercury Cougar The last Cougar convertible and the last 351 Cobra Jet year, with production up to 60,629 as buyers shifted to the XR-7.
- Mercury Montego GT The Montego GT fastback's second and last year; a vehicle profile reports 4,464 built.
- Oldsmobile Cutlass, 4-4-2 and Hurst/Olds On the new Colonnade Cutlass the 4-4-2 was a W-29 appearance and handling option, and the Hurst/Olds came in white or, for the first time, black: 1,097 built.
- Plymouth Barracuda and 'Cuda V8 only: the 318 became standard on both Barracuda and 'Cuda, the 340 moved to the option list, and production rose for the only time after 1970.
- Plymouth Duster 340 and 360 The 340's last year in the Duster produced 15,731 cars with power front disc brakes now standard, and the Spacemaker Pak fold-down rear seat joined the line.
- Plymouth Road Runner A secondary count puts production back up to 19,056, the highest of the 1971-1974 Satellite-based years.
- Pontiac Firebird and Trans Am The Super Duty year: 4,802 Trans Ams, 252 of them SD-455s.
- Pontiac GTO A GTO option on the new Colonnade LeMans, with the 400 standard and a 455 optional; 4,806 built.
- Pontiac Grand Am Pontiac's Colonnade GT with an Endura nose and a 400 or 455; 43,137 built, the Grand Am's best year, with 1,058 four-speeds.
- Pontiac Grand Prix The Colonnade-body Grand Prix arrives, with the 400 standard and the 455 in the SJ.
- Pontiac Tempest and LeMans The Colonnade LeMans arrives, with GTO and GT options for the two-door models and a Super Duty 455 listed for the LeMans in Pontiac's dealer book.