1973 Buick Century Gran Sport 455 Stage I
2dr Hardtop Coupe
8-cyl. 455cid/270hp 4bbl
With an experienced team and a lot of data.
In the middle-1970s, the Century line was Buick’s intermediate passenger car, available in several trim levels including the base Century, the Luxus, and the Regal, plus a Gran Sport (GS) option available on any trim level that substantially increased engine performance. The Century line used GM’s mid-sized A-body, similar to the Oldsmobile Cutlass, Chevrolet Malibu, and Pontiac Grand Prix. In this era of higher fuel prices and tightening environmental standards, Buick was looking to smaller engines and cars to meet market and regulatory standards.
Body styles for the base Century line included 4-door hardtop sedans and coupes, and a 4-door station wagon that could be configured for 6 or 9 passengers. The Century Luxus trim level traded the 4-door hardtop coupe for a 2-door hardtop coupe with the famous "Colonnade" styling that put an angled rectangular opera window between heavy B- and C- pillars. The Regal trim was available only in the 2-door hardtop colonnade coupe.
Engine options for the 1973 Century line included the base 350-cid small block V-8 rated at 150 hp with a two-barrel carburetor, or the upgraded V-8 at 175 hp with a four-barrel carb. Gran Sport cars with the small block received an engine rated at 190 hp. Big block V-8s were also available, displacing 455 cubic inches and delivering 225 hp. The Century Gran Sport Stage 1 package combined with the big block option yielded an impressive 270 hp from the 455. A 3-speed manual transmission with column shift was standard, but most Centuries received a Turbo-Hydramatic 350 or 400 automatic transmission based on their engine power.
For 1974, body styles stayed the same except the 4-door coupe was dropped in favor of extending the 2-door colonnade coupe throughout the line. A 4-door hardtop sedan was also available in Regal trim. Engine and performance options became more complicated, but amounted to four different Gran Sport packages. A base GS offered styling and suspension upgrades including Posi-traction, while two GS 455 packages (A5 and A9) offered more engine power with the big block. Once again, the highest output package was a GS Stage 1, rated at 255 hp.
The 1975 model year was one of change, with the Luxus trim level replaced by a Century Custom designation, and the base Century was split into the Century Special with a 231-cid V-6 rated at 110 hp, or a Century with either the V-6 or the 350 V-8 rated at 145 hp. Both the Custom and Regal levels were available with the V-6 or V-8.
The power upgrade available in the 1975 Century line was a four-barrel carburetor good for just 165 hp. The big block was gone from the Century line in this year, but that was no great loss as it was choked down to 185/205 hp. Body styles remained more or less the same, except the colonnade became a triangular window.
For 1976, body style options contracted to colonnade 2-door coupes and 4-door sedans, plus the wagons. The V-6 was the standard engine, still at 110 hp, with two optional 350 V-8 engines at 140 or 155 hp. A t-top “Hurst Hatch” roof was also available as an option.
For 1977, the final year of this generation, Century buyers could choose from the base V-6 at 105 hp, a 305-cid V-8 at 145 hp (California model), or three 350-cid engines at 140, 155, or 170 hp. Wagon buyers could also opt for the 403-cid big block at 185 hp. Cars equipped with the V-6 could also select a fuel economy option that featured a taller rear axle, specially tuned Turbo-Hydramatic transmission, and an air conditioner cutoff at wide open throttle.
Collectors will of course want to seek out the Century Regal coupes with the GS option packages, especially the GS 455 Stage 1 packages from 1973 and 1974. Wagon enthusiasts can also find the big block treatment for a bargain price.