1973 Buick Century GS 455 Stage-1 Colonnade Sun Coupe

Generously Lent by  Philip & Grace Roitman

·       455 Cubic Inch V8 360 Horsepower Engine

·       1 of 45 Stage 1 Gran Sport Sun Coupes built in '73, 1 of 23 with Electric Sun Roof

·       Voted the People’s Choice Award at the 2023 Audrain Concours

The options on this car make it quite rare. One of just 45 Sun Coupe models made, only 23 incorporating an A.S.C. hidden electric sunroof in 1973, and one of only four made in S.C.O. Code O paint, perhaps the only of the four cars painted in yellow.

The 1973 Buick Gran Sport Stage 1 Sun Coupe was one of the last remaining performance cars available at the end of the “Muscle Car” era before EPA emissions and safety regulations changed the automotive industry in the 1970’s.  The body acquired beefier rollover protection which added just under 400lbs to new “Colonnade Body,” named after the classical architectural orders.

Based on the mid-sized Buick Century platform, the Stage 1 performance option package mated a powerful 455 cubic inch V8 engine with a 3-speed turbo Hydramatic transmission, 4-barrel carburetor, performance wheels and bucket seats. The Gran Sport (also designated as a GS model) was the more mature and well-mannered Buick performance model. But, in its Stage 1 form would still offer the highest torque output of any production passenger car engine at 510 ft lbs, a record number that was upheld until the release of the V-10 Dodge Viper 30 years later. The Stage 1 engine used special camshafts and larger valves to increase performance.  Front disc brakes and radial tires were standard equipment.

Due to rising insurance costs, fuel economy, and increased emissions restrictions, sales of Buick’s GS 455 vehicles were quite low in 73, with fewer than 728 units made with the Stage 1 package and even fewer with the factory installed electric controlled retractable sunroof, as this car.  The Gran Sport Stage 1 Coupe was still a serious competitor in the muscle car market with quarter mile times below 16 seconds and 0-60 mph speed runs in the 8 second range.  Subsequent GS models saw a marked decrease in top speed as the cars became heavier and more restricted.

When pitted against other similar sized performance cars in the early 70’s, the Gran Sport Stage 1 quietly beat out the Pontiac Grand Am Super Duty, AMC Javelin, Ford Mustang GT, and Chevrolet Chevelle Laguna in a Motor Trend Magazine American Car shoot out, losing only to the Dodge Charger by a very small margin in acceleration tests. 

At the 2023 Audrain Concours, this pristine condition example of the 73 Gran Sport Stage 1 was voted by attendees as the “People’s Choice Award” winner, beating over 175 other vehicles in the show.  It was a testament to the care and preservation given to this car by its owners Phillip and Grace Roitman.

Specifications

·       Engine: GM Buick 455 cu in Big-Block V8, 4-barrel Quadrajet carburetor, oversize valves and camshafts

·       Transmission: 3-speed Turbo Hydro-Matic 400

·       Power: 270 hp at 3000 rpm, 390 ft-lb torque

·       Performance: 0-60 mph 8 sec, ¼ mile: 15.3 sec

·       Top Speed: 112 mph

·       Weight: 4030 lbs, weight to horsepower ratio: 14.93 lbs/hp