Quartet of Stage 1 Buick Gran Sports from a single collection to cross the block in Indy

Introduced in 1965 as a high-performance option package for Skylarks and Rivieras, Buick's Gran Sport models quickly earned a reputation as "the gentleman's muscle car," blending equal parts performance and luxury. The Gran Sport lineup continued to evolve year upon year, reaching its performance pinnacle in 1970 with the debut of the Buick GS 455 Stage 1. On Friday, May 18, four Stage 1 Buick Gran Sports from the Matt Wagoner Collection – one each from model years 1970-'73 - head to Mecum's auction in Indianapolis, Indiana.

For 1969, Buick made its Stage 1 package – previously available via the parts counter only – a factory-installed option. Consisting of better-breathing cylinder heads, a high-lift camshaft, heavy-duty valve springs, hollow pushrods, a higher-capacity fuel pump, a revised oil pump, a larger-diameter exhaust, a modified Quadrajet carburetor and a new distributor, the Stage 1 package raised the 400-cu.in. V-8's output from 340 horsepower to 350 hp, while the stated 440 lb-ft of torque remained unchanged. On paper, it hardly seemed worth the expense, but the real-world numbers told a different story, and those in the know put the output of the Stage 1 package at close to 390 hp.

For 1970, Buick upped the GS's game even further, replacing the 400-cu.in. V-8 with a 455-cu.in V-8, rated at 350 hp and 510 lb-ft of torque in base models, with Stage 1 variants once again getting a (wink, wink, nudge, nudge) 10 hp boost. Road & Track reported a 0-60 time of 6.4 seconds and a quarter-mile time of 14.4 seconds at 96 mph for a Stage 1 GS 455 – with both a driver and passenger in the car. For those looking to fly – literally and figuratively – beneath the radar, there may have been no finer choice from an American manufacturer in 1970 than Buick’s understated-but-not-underpowered GS 455 Stage 1.

1970 Buick GS 455 Stage 1.

Which brings us to the first car available in Indianapolis, a 1970 Buick GS 455 Stage 1, built as a factory prototype and show car and finished in Fireglow Pearl with a white interior. Assembled as a white GS 455 in Stage 1 trim, the car was pulled from September 1969 production and finished in its unique pearlescent red livery, while inside the standard black bits (like the A-pillar trim, carpeting, steering wheel and kick panels) were replaced with white counterparts. To liven the monochromatic interior up a bit, tangerine-colored seat belts were added, and, accompanied by a white Buick GSX, the GS 455 Stage 1 made the rounds of the show circuit, luring performance buyers into Buick showrooms.

Their life in the spotlight over, both cars were destined for the crusher, at least until Ohio dealership Len Immke Buick intervened, buying the show cars to promote their performance business. A reported agreement that the cars not be sold to consumers didn’t last long, and the red GS 455 Stage 1 soon found a home with a buyer that enjoyed the car on street and strip. This original owner held onto the car until 2003, when it was purchased by John Chamberlain with less than 13,000 miles on the odometer. A comprehensive restoration – finished circa 2005 – followed, and the car appeared in the August 2005 issue of Hemmings Muscle Machines magazine. Five years later, the car earned Gold Certification at the 2010 Buick Performance Group Nationals.

In 2014, the prototype – still carrying white carpeting – appeared at Mecum’s Chicago sale, but failed to meet the reserve and was not sold. Four years later, the car now wears black carpeting (a more sensible choice for a car that’s driven, even occasionally) and will once again be crossing the block at a Midwest Mecum sale, perhaps with a different outcome.

The 1971 Buick GS 455 Stage 1 convertible to be offered from the Matt Wagoner Buick Gran Sport Collection was one of an estimated 25 models constructed as Zone Demonstrator cars for use by regional executives. To highlight the range of options available to consumers, each was equipped with air conditioning; power steering, power brakes, power windows and power door locks; front disc brakes; the F41 Rally Ride suspension; chrome 15x7-inch Rally wheels with G60-15 raised white letter tires; Rallye gauges with tachometer; tilt Rallye steering wheel; the Convenience Lighting Group; Soft Ray tinted glass; and an AM radio with an 8-track player. Each was finished in Cortez Gold with a white top, and of the Zone Demo cars built (and later sold through dealerships as discounted demonstrator models), roughly 11 are known to survive today.

The example heading to auction in May has been restored to what’s described as a “very high standard,” though that isn’t to say the Stage 1 drop-top is all show and no go. In the interest of added performance, its period-correct 455-cu.in. V-8 has been tuned to produce a dyno-measured 416 hp and 541 lb-ft of torque, a significant gain over the stock 1971 output of 345 hp and 460 lb-ft of torque. Likewise, for improved driveability (and greater fuel economy) a 700R4 automatic transmission with overdrive takes the place of the original Turbo Hydra-Matic 400.

For 1972, the GS 455 Stage 1 carried over with the previous year’s lower 8.5:1 compression instead of the 1970 model’s 10.5:1. Even without additional changes, reported horsepower numbers fell significantly, to 270 hp and 390 lb-ft of torque, as automakers began rating output in net terms (including performance-robbing items like air cleaners and muffled exhaust systems) instead of the theoretically impossible gross ratings.

The 1972 GS 455 Stage 1 coupe from the Matt Wagoner collection appears to be restored, with a claimed 85,000 miles on the odometer and a numbers-matching drivetrain. One of 728 Stage 1 models built in 1972, this well-optioned example includes air conditioning; power steering and power brakes with front discs; tinted glass, a tilt steering wheel, and an AM/FM radio.

In 1973, GM introduced its Colonnade body style, and at Buick, the new Century replaced the Skylark as the basis for the Gran Sport models, which were once again identified their full name instead of just their initials. Those wanting more style than substance could order a Gran Sport with a sedate 350 V-8, fed by a two-barrel carburetor and rated at 150 horsepower; at the opposite end of the spectrum, however, the Stage 1 option – complete with its big-block 455 V-8 carried over, still rated at 270 hp and 390 lb-ft of torque, net.

The 1973 Buick Gran Sport Stage 1 to be offered represents the most desirable of all configurations, as it comes equipped with a four-speed manual transmission and was one of just 92 Stage 1 models built without an automatic transmission that year. A well-optioned example, the Colonnade Gran Sport reportedly carries its original interior and a restored exterior, as well as an enhanced original engine built to 1970 performance specifications, for an output (gross, not net) of 360 hp and 510 lb-ft of torque.

Mecum’s Indianapolis sale takes place on May 15-19 at the Indiana State Fairgrounds. For additional information, visit Mecum.com.