1973 · Buick · United States
1973 Buick Century Gran Sport: the new Colonnade body
On the new Colonnade A-body the GS became a Century Gran Sport package; 6,637 were built, 728 with the 455 Stage 1.
United States · researched through 2026-09-22
For 1973 General Motors replaced its A-body intermediates with the new Colonnade design, and Buick dropped the standalone GS model in favor of a Gran Sport sub-series on the Century 350 coupe. Hemmings describes the base package as tape stripes and a blacked-out grille plus an electric clock, wheel-arch moldings, better gauges, and courtesy lamps, priced at $173 over the $3,057 base Century 350.1
Production is given as 6,637 Gran Sports for 1973, of which 979 carried the 455 and 728 the 455 Stage 1; this record's own production note states plainly that no 350-engine count was found, since the cited Hemmings article does not state one despite giving the 455 and Stage 1 figures directly. A separate note flags that Wikipedia repeats the same Hemmings-sourced totals but adds a 350 figure, 4,930, that does not appear anywhere in the Hemmings article itself, so that unstated figure is not carried in this record. Century two-door pillar coupe production, the host body for the Gran Sport package, is given as 56,154 across all trims, a figure this record's own production note is careful to describe as including non-Gran-Sport cars rather than as a Gran-Sport-specific count.1,2,3
Four engines are documented: the base XA 350 two-barrel with single exhaust at 175 hp, the optional XB 350 four-barrel with dual exhaust at 190 hp, the optional XF 455 at 225 hp, and the optional XS 455 Stage 1 at 270 hp, the last requiring the Turbo Hydra-Matic 400 and carrying larger valves than the standard 455, 2.120-inch intake against 2.000 and 1.755-inch exhaust against 1.625, along with a standard 3.42 axle and Positraction. Four transmissions are documented: a three-speed manual with column shift standard, a Muncie four-speed with floor shift optional, the Turbo Hydra-Matic 350 as the only automatic offered with the 350, and the Turbo Hydra-Matic 400 with the 455, required on the Stage 1.1
The Century 350 coupe's curb weight is given as 3,718 lb, and the Gran Sport's standard axle ratio as 3.08:1, rising to 3.42:1 on the Stage 1. Fifteen paint codes are charted from a Buick-line 1973 list, with this record's own paint note explaining that three additional codes on the same source page are marked Riviera-only and excluded here as out of scope for this subject. Interior trim is documented only at the level of the Century two-door coupe generally, ten codes covering green, blue, neutral, black, saddle, white, and oxblood, with this record's own interior note stating plainly that Gran-Sport-specific trims are not separated from the wider Century coupe's trim chart in the available source.1,3
Identification detail carries an internal inconsistency this record does not resolve. Hemmings gives the fifth VIN character as J or K for the 350 four-barrel, T for the Gran Sport 455, and V or W for the Stage 1, matching a decoded example VIN, 4V57J3H446727, that breaks Buick, series, body, engine letter, year, plant, and production number apart. A separate TeamBuick engine-code table, however, uses a different letter scheme entirely for the same four engines, XB for the 350 at 175 or 190 hp, XF for the 455 at 225 hp, XS for the 455 at 250 or 260 hp, and XA for the 455 Stage I at 270 hp, which reassigns the XA, XB, XF, and XS codes this record's own engine entries use for the 350 two-barrel, 350 four-barrel, 455, and Stage 1 respectively. This record carries both letter schemes as each source's own documented content rather than reconciling them into one, since neither source explains why the two disagree.1,3
Fact sheet · 1973 · United States
The numbers
1973 Buick Century Gran Sport — On the new Colonnade A-body the GS became a Century Gran Sport package; 6,637 were built, 728 with the 455 Stage 1.
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.
Key facts
Production
| What was counted | Count | Basis | Status |
|---|---|---|---|
| Century Gran Sport, all engines1,2 Century Gran Sport · Colonnade coupe · 350, 455, 455 Stage 1 · not stated by source Wikipedia repeats Hemmings (one lineage) and adds a 350 figure (4,930) that Hemmings does not state. | 6,637 | built, model-year | Reported |
| What was counted | Count | Basis | Status |
|---|---|---|---|
| Century Gran Sport 4551 Century Gran Sport · Colonnade coupe · 455 (XF) · not stated by source | 979 | built, model-year | Reported |
| Century Gran Sport 455 Stage 11 Century Gran Sport · Colonnade coupe · 455 Stage 1 (XS) · Turbo Hydra-Matic 400 · not stated by source | 728 | built, model-year | Reported |
| What was counted | Count | Basis | Status |
|---|---|---|---|
| Century 2-door pillar coupe (4AD37), all trims (Gran Sport host body)3 Century · 2-door Colonnade coupe · not stated by source The Gran Sport was a package on this body; the row includes non-GS cars. | 56,154 | built, model-year | Reported |
Engine rows are subsets of the Gran Sport total. No 350-engine count is used because the cited article does not state one.
Prices when new
| Model | Price | Basis |
|---|---|---|
| Century 350 coupe, base (before Gran Sport)1 | $3,057 | base price as given by Hemmings, 1973 |
Prices are the nominal dollars of the day, not adjusted for inflation.
Engines
| Engine | Factory rating | Availability | Built |
|---|---|---|---|
| XA · 350 V-8 2-barrel, single exhaust1 350 cu in · Rochester 2-barrel | 175 hp (SAE net (as given by Hemmings)) | base, Gran Sport | Not yet sourced |
| XB · 350 V-8 4-barrel, dual exhaust1 350 cu in · Quadrajet 4-barrel | 190 hp (SAE net (as given by Hemmings)) | optional | Not yet sourced |
| XF · 455 V-81 455 cu in · 4-barrel | 225 hp (SAE net (as given by Hemmings)) | optional | 9791 Reported |
| XS · 455 V-8 Stage 11 455 cu in · 4-barrel | 270 hp (SAE net (as given by Hemmings)) | optional; Turbo Hydra-Matic 400 required | 7281 Reported |
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 |
|---|---|---|
| 3-speed manual, column shift1 | base | Not yet sourced |
| M21 · Muncie 4-speed, floor shift1 | optional | Not yet sourced |
| Turbo Hydra-Matic 3501 | only automatic with the 350 | Not yet sourced |
| Turbo Hydra-Matic 4001 | with 455; required with Stage 1 | Not yet sourced |
Options and packages
| Code | Option | Price | Installed |
|---|---|---|---|
|
Gran Sport package (Century 350 coupe)1 | $173 | 6,6371 Reported |
Paint
| Code | Color | Built |
|---|---|---|
11 |
Arctic White3 | Not yet sourced |
24 |
Medium Blue (poly)3 | Not yet sourced |
26 |
Mediterranean Blue (poly)3 | Not yet sourced |
29 |
Midnight Blue (poly)3 | Not yet sourced |
42 |
Jade Green (poly)3 | Not yet sourced |
44 |
Willow Green (poly)3 | Not yet sourced |
46 |
Green-Gold (poly)3 | Not yet sourced |
48 |
Midnight Green3 | Not yet sourced |
56 |
Colonial Yellow3 | Not yet sourced |
60 |
Harvest Gold (poly)3 | Not yet sourced |
64 |
Silver Cloud (poly)3 | Not yet sourced |
66 |
Taupe (poly)3 | Not yet sourced |
68 |
Brown (poly)3 | Not yet sourced |
74 |
Burgundy (poly)3 | Not yet sourced |
81 |
Bamboo Cream3 | 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 |
|---|---|---|
100/120 |
Century 2-Door Coupe: Green, material not marked3 | Not yet sourced |
130 |
Century 2-Door Coupe: Green, material not marked3 | Not yet sourced |
111 |
Century 2-Door Coupe: Blue, material not marked3 | Not yet sourced |
114/104 |
Century 2-Door Coupe: Neutral, material not marked3 | Not yet sourced |
124/134 |
Century 2-Door Coupe: Neutral, material not marked3 | Not yet sourced |
108/128 |
Century 2-Door Coupe: Black, material not marked3 | Not yet sourced |
138 |
Century 2-Door Coupe: Black, material not marked3 | Not yet sourced |
126/136 |
Century 2-Door Coupe: Saddle, material not marked3 | Not yet sourced |
135 |
Century 2-Door Coupe: White, material not marked3 | Not yet sourced |
139 |
Century 2-Door Coupe: Oxblood, material not marked3 | Not yet sourced |
Specifications
| Measure | Value | Applies to |
|---|---|---|
| Curb weight, Century 3501 | 3,718 lb | Century 350 coupe as given by Hemmings |
| Standard axle ratio1 | 3.08 :1 | Gran Sport; Stage 1 3.42 |
Identification
- VIN engine code
- Fifth VIN character: J or K for the 350 four-barrel, T for the Gran Sport 455, V or W for the Stage 1 (per Hemmings).1
- VIN
- E.g. 4V57J3H446727 as printed: 4 = Buick; series letter (D = Century); body (37 2-door coupe); engine letter (H/J/K 350; T/U 455; V/W 455 Stage I); year (3); plant (C, G, H, L Van Nuys, X, Y, Z); production number.3
- Engine codes
- XB 350 175/190 hp (dual exhaust); XF 455 225 hp; XS 455 250/260 hp; XA 455 Stage I 270 hp (TeamBuick ratings).3
Identification
Read a 1973 Buick VIN
The VIN decoder runs in your browser and never sends the VIN anywhere. How the factory numbered this year's cars:
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.
- 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 GTX, Belvedere and Satellite 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.
- 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.