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Buick Gran Sport

Buick Gran Sport, 1970 455 Stage 1

Skylark Gran Sport

The 1965 Skylark Gran Sport was the intermediate Buick Skylark with the Gran Sport option added. Although a Script error: No such module "convert". V8 was already offered in the Skylark, the Gran Sport had the largest engine permitted by GM - a Script error: No such module "convert". Buick V8. This engine was actually Script error: No such module "convert"., but called a "400" by Buick because that was the maximum engine size limit set by General Motors for the intermediate body cars. This engine produced 325 hp (242 kW) and 445 lb·ft (603 Nm) and was known as the "nailhead" engine. Buick sold more than 15,000 Skylarks with the Gran Sport option that first year, and almost as many the next. It was renamed the GS 400 in 1967, and the Gran Sport became its own model in (about) that same year along with a new "400" engine quite different from the famously reliable but becoming-obsolete nailhead engine design that was first introduced in 1953. Sales fell somewhat in the face of increasingly higher-performance and more popular muscle cars from other marques when compared to those from the more stodgy and expensive Buick. Buick, however stepped it up a notch when introducing the Stage 1 option in 1969. This limited production (less than 1,500 cars in 1969) version delivered 340 hp (253 kW) and 440 lb·ft (597 Nm).

The name Gran Sport replaced the GS moniker with the 1973 Gran Sport, and was again revived in the late eighties on the FWD Skylark model with various performance options added.

Gran Sport 340/350

In 1967 Buick added a Script error: No such module "convert". version, there was the GS 340 and the GS California sub-model, little more than the Skylark hardtop with new badging and trim,[1] The 340 produced Script error: No such module "convert". and 365 lb·ft (495 Nm), and less than 4,000 cars were sold. It was replaced the next year with the GS 350 and similar GS California; these used Buick's Script error: No such module "convert". small-block engine. A California 2-door coupe appeared in 1969;[2] total GS sales for the year, not counting the new California coupe, were 12,465 (4,933 GS 350s, 7,532 GS 400s).[2] Sales of the GS 350 for 1970 climbed to 9,948;[3] in addition, 10,148 Script error: No such module "convert". 2-doors were built.[3] The Gran Sport 350 outlived its big brothers, lasting until V8 Gran Sport production stopped in 1975, replaced by the Gran Sport 231.

Gran Sport 400

In 1968 and 1969 Buick offered the GS 400 in a convertible and hardtop model. Standard issue of the GS 400 was a 400 cubic inch (6.6L) engine (with likely lower stated horsepower rating to keep insurance premiums lower) of 340 horsepower (350 hp stage 1 ) and 440& bsp;ft. lbs. torque, a four barrel Rochester carburetor, dual exhaust, 2.93 standard gear ratio optional ( limited slip differential, (3.64 stage 1 option, 3.42 with A/C ), and the available three speed turbo hydra-matic 400 automatic transmission (revered as the finest automatic transmission ever built), u shape shifter and linkage, located at the front of a center console. A 1968 or 1969 GS400 equipped with the TH400 auto transmission was faster off the line, and up to 70 mph than the 4-speed GS455 to come. Shift pattern for the TH400 Park, Reverse, Neutral, Drive, Second, First. A standard 3 spd or optional 4 spd manual gearbox was also available. Compression ratio on this engine was a very sensible 10.25:1, which allowed for the use of any grade gasoline to be used in normal driving without pinging.

Gran Sport 455

The 400 was replaced for 1970 with the {7.4 litre} Buick V8, used in the GS 455. The base model V8 was rated 350 hp (260 kW) and Script error: No such module "convert". at 2800 rpm. In the optional Stage1 trim it was rated** 360 hp (268 kW) and 510 lb·ft (691 Nm) at a low 2800 rpm. As with all American engines produced prior to the 1972 model year, these were SAE gross ratings, which are generally significantly higher than SAE net ratings and are not indicative of what actual production engines produce in their "as installed" condition (with all engine accessories and full exhaust system in place). The fastest magazine test results from this period were obtained by MOTOR TREND Magazine, which managed to extract a 13.38 ET @ 105.5 MPH from their 3,810 pound GS Stage 1 coupe test car. Using Hale's Trap Speed formula, this result indicated actual "as installed" peak HP of approximately 360 SAE Net (ironically the same as its advertised Gross Figure, meaning this engine was very conservatively rated for that time period). The use of the larger sized 455 block created a maintenance problem by the exhaust manifolds being in too close proximity to the upper and lower A-arm bushings. Heat would literally melt the bushings after a relatively short period of time; rapid tire wear and front end alignment difficulties were the first sign of this common problem.

Coming correct with a gigantic 455 cid V8 and a Hurst four-speed, the GSX had all the grunt any self-respecting son of the seventies needed. Power figures are elusive and confusing. Officially, the factory quoted 360 hp @ 4,200 rpm. No doubt this was true, but what did the mill stonk at say 5,200 rpm? At least 400 horses, if not a bit more (415 to 425 hp). GM fudged the numbers because insurance companies at the time were charging huge draconian penalties premiums based on horsepower. The corporate wink, wink saved customers from insurance payments bigger than their car payments. Luckily insurance companies didn't care about torque, as it is hard to hide 510 lbs. ft. of the good stuff at a 2,800 rpm.

The December 2004 issue of Musclecar Enthusiast" conducted an engine dynamometer test of a freshly rebuilt and well documented 1970 455 Stage 1 (bored .040" over to 464 cubic inches and minus the power-robbing factory engine fan, air cleaner assembly and mufflers). In that condition and with factory timing and carburetor tuning, the engine produced a maximum of 360.9 HP. Optimal carburetor and ignition tuning yielded a peak HP reading of 381.7 HP - again with no engine fan, air cleaner or mufflers in place. While urban legend would have us believe that these engines made "420 HP from the factory," actual empirical results prove otherwise. Although another dynamometer test on a 1970 Skylark GS Stage I showed 471 SAE gross hp, which is more consistent with the engine producing about 360 SAE net hp.

The Stage 1 engine option used cylinder heads that, while using raw castings of the same pattern as all of the other Buick 455s sharing the same model year, were machined differently in order to accept larger valves (2.13" intake and 1.755" exhaust), and to produce smaller compression chambers for increased static compression ratio. The option also included a more aggressive camshaft, a specially tuned 4-barrel Quadrajet carburetor, more aggressive ignition timing,5/8 inch oil pickup tube and a higher numerical final drive, and was available with either Turbo-Hydramatic 400 3-speed automatic transmission, or a Muncie M-22 4-speed manual transmission (although it was later discovered, and confirmed, that one 1970 GS Stage 1 convertible was produced with a 3-speed manual and a standard 3.64:1 Positraction axle ratio). Stage 1 cars equipped with air conditioning received a 3.42 axle ratio.

While powerful in production form, the Buick 455 (including Stage 1) engines had problematic engine blocks. All used 2 bolt main bearing caps; the oiling system was under-sized for high rpm use (including Stage 1 engines) and thin walls in the lifter valleys promoted cracking. The magic of the Stage 1, it would seem, was primarily attributable to its advanced (for the period) cylinder heads and the relatively high mid-range horsepower they produced.

The relatively unknown, very expensive, and very rare 1970 GS 455 Stage 1 drew a great amount of attention and controversy in the muscle-car world when in the 1980s it was listed as faster than any of the Chrysler Hemi cars in the original "50 fastest muscle cars" list. This Hemi vs. Stage 1 controversy has prompted several contests to settle the issue; it remains an unsettled matter and has been a great boon to car magazine sales over the years.

There was also a rare Stage 2 option produced. This was a dealer-installed package (known as a "dealer option"), first offered in 1969. It included a cam, headers, intake manifold, high compression forged pistons, hollow pushrods, and some calibration changes to the ignition and carburetor. If the car was ordered with the Stage 2 package, the parts were shipped in the trunk of the car. In 1970(?) the Stage 2 package included special D-port exhaust port Stage 2 heads, matching Kustom brand headers, a radical cam, high compression forged pistons, Edelbrock B4B aluminum intake, Holley carburetor, and other equipment for racing. Few Stage 2s were ever used on the street and Buick only ever factory assembled 1 Stage 2 test unit, it was a factory GSX clone test mule with 4-speed manual transmission used for speed testing. That GSX test mule was equipped with 4.78 gearing and was driven on the streets and tracks on the West Coast. The Stage 2 package's existence was not made public until 1972 when the Stage 2 parts could be ordered in any combination. There is little documentation about any Stage 2 cars that were sold. Three are known to exist. One was campaigned by Kenne-Bell/Reynolds Buick and the other was known as the Jones-Benisek car. The Jones/Benisek car is known to have been delivered as a Stage 1 car with all the Stage 2 components in the trunk in GM boxes.The third one is known as Wiley Coyote and the Turner car. It was originally owned by Bob Thetford and campaigned as "Wiley Coyote" in the NHRA . Sponsored by Kenne-Bell and Dunn Buick in Oklahoma city . Later it was owned by Jim Turner and was very successful in NMCA winning 5 National Records . All three of these cars were built as Stage 1 cars at the factory.

Output and sales for the assembly-line cars were down after 1970 largely due to reduced engine compression ratios and a change from gross to net horsepower ratings. In later years, air quality regulations further limited the power in part due to the addition of catalytic converters and single exhaust pipes. However, Stage 2 parts were available over the Buick parts counter although the Stage 2 heads were discontinued after about 75 sets were produced. The discontinuation was due to porosity problems with castings.The discontinuation of the Stage 2 also was due to the ever tightening emission standards which resulted in lower performance.


GSX / GSX Stage1 was the optional high performance package available on the GS 455 starting in 1970. The GSX ornamentation package was a $1,100 option on the GS455. The GSX was made to attract attention, and to help showroom traffic in an effort to increase sales. The GSX was Buick's answer to Pontiac's GTO Judge and Oldsmobile's 4-4-2 W-30. Buick advertised it as "A Brand New Brand Of Buick" and "Another 'Light Your Fire' Car From Buick". It was only available with the standard big block 455 engine or the optional Stage 1 engine the first year. It was not a very popular model, and only 678 GSXs were produced in 1970. Just 278 were equipped with the standard 455, a further 400 being equipped with the optional Stage 1 performance package. The performance of a GSX (or GS) Stage-1 is comparable to that of the HemiCuda, but in a much more luxurious car. This is partly due to the light weight of the 455 which is roughly Script error: No such module "convert". less than the 426 Hemi or Chevrolet 454. The engine's performance also relies on the tremendous torque this engine produces - 510 lb-ft (gross) at 2800 rpm. Production dropped in 1971 to only 124, and again to 44 in 1972. These numbers include the available 350-4 bbl option, the standard 455, and the Stage 1 engines.

In 1970, the GSX option was available in only two colors, Saturn Yellow and Apollo White (in 1971 and 1972 6 other colors were available for the GSX). All GSXs had the distinctive full body length black stripe that crossed over the standard equipment rear spoiler and was outlined in red pin stripes. A large area of the hood was also black with a hood mounted tachometer (Buick engineers disliked the hood tachometer because it was a Pontiac part) and black front spoiler. Also standard equipment were black bucket seats, floor shifter, wide oval tires, quick ratio steering and anti-sway bars. Some other options were automatic transmission or four speed manual. Four restored versions sold in Barrett-Jackson's 2010 LasVegas auction for as much as $80,000.

After 1970, the 1971 and 1972 GSX became an option that was available on any Gran Sport. Many GSXs survive to this day and can be seen at the Buick Gran Sport Nationals held annually in Bowling Green, KY in the middle of May along with many other examples of '60s, '70s and '80s Buick performance models. Another Buick event is the Buick Performance Group Nationals which is held at National Trail Raceway in Columbus,Ohio during the early month of August.

The GSX and big-block V8 were dropped after 1974. In 1974, the GSX consisted of a trim package on Buick's small, X-bodied Apollo. Three engines were available on the 1974 GSX: the Chevrolet supplied 250 6-cyl.,and two Buick engines:the 350 2 barrel and 350 4 barrel versions.

Riviera Gran Sport

File:Riviera GS.JPG
1968 Riviera GS

The Riviera Gran Sport was a high-performance version of the Buick Riviera, produced from 1965 through 1975.

In 1965, it was called Riviera Gran Sport and the later models were still officially called Gran Sport but showed GS badges instead of Gran Sport. Unlike the mid-size GS models, the Riviera and Wildcat GS package included a standard 3.42 positraction rear axle until 1973. The 1965 (and optional in 1966) Riviera Gran Sport also came with a 425 cubic "Super Wildcat" engine, with dual carbs and dual snorkel chrome air cleaner. You could add H2 option (Ride and handling package) for even better road handling. Shorter gear ratio for steering, 1 inch lower suspension.

Wildcat Gran Sport

File:1966 Buick Wildcat Convertible.jpg
1966 Buick Wildcat GS convertible

Another GS option package was available on the Buick Wildcat and Wildcat Custom, hardtop and convertible. The GS package included a 3.42 ratio posi rear, variable rate suspension springs, quick ratio steering box, heavy duty sway bars, and a switch-pitch turbo-hydramatic 400 transmission. The addition of the Y48 option gave the purchaser a pair of Carter AFB four barrel carburators, and finned aluminum valve covers on the 425 nail head engine. This was a one-year only option, existing in 1966 only. The Y48 option was delivered in the trunk and installed by the dealer.

Century Gran Sport

1973 Buick Century GS

In 1973-75 and in 1986, there was a Century Gran Sport. For 1973, Buick renamed its intermediate line from Skylark to Century, a nameplate previously used on Buick's full-sized performance cars from 1936 to 1942 and 1954 to 1958. Like all GM intermediates, the 1973 Century received new Colonnade styling, which amounted to pillared hardtop sedans, coupes and station wagons - each of which utilized frameless windows along with fixed rear side windows, and convertibles were discontinued. The GS became the "Gran Sport" and was now an option package on the semi-fastback Century 350 Colonnade coupes. The "Gran Sport" option included decals on the rear fenders and trunk lid reading "gran sport" along with suspension and appearance upgrades.

The standard engine was a 150-horsepower 350 two-barrel V8, which was the standard engine for all Centurys. In addition to the 175-horsepower 350 four-barrel V8 (with single exhaust), the 190-horsepower 350 four-barrel V8 (with dual exhaust) was available only on the Gran Sport. Two 455 cubic-inch V8s were available including the 250-horsepower four-barrel and the Stage 1 four-barrel rated at 270 horsepower (both with dual exhaust) - all net figures and similar to the 1972 models. More than 700 '73 Century GS models were built with the Stage 1 455, the majority with the three-speed Turbo Hydra-matic 400 transmission and a small number with the four-speed manual transmission.

The 1974 Century "gran sport" received the same exterior and interior trim changes as other Century models. The same selection of engines was carried over from 1973 including the 350 four-barrel, 455 four-barrel and the 455 Stage 1 four-barrel (the 455s downrated to 245 and 255 net horsepower respectively) and, like all other '74 Century GS engines, only available with a Turbo Hydra-matic transmission. Radial tires were a new option for 1974 along with reclining Strato bucket seats.

For 1975, the Century GS, or "gran sport" entered its third and final year on the Colonnade body. It was reduced to a mere appearance/handling package as the 455/Stage I options were discontinued and Buick's revived 231 cubic-inch V6 was the standard engine, mated to a standard three-speed manual transmission or optional Turbo Hydra-matic. The only optional engines were two 350 V8s, a two-barrel 155 horsepower version or the four-barrel option rated at 175 horsepower and offered only with the Turbo Hydra-matic. Both engines were also mated to catalytic converters for the first time this year, which mandated the use of unleaded gasoline and precluded the availability of true dual exhaust systems. Radial tires were now standard equipment and the Strato bucket seat option reverted to the non-reclining version.

Both the Century GS and the larger Riviera GS (which also had been continually produced since 1965) were discontinued after the 1975 model year due to sagging sales for high-performance cars following the 1973-74 energy crisis and subsequent trends toward smaller and more fuel-efficient cars. Performance versions of the Century (and its companion Regal line) and Riviera would return in the late 1970s with the advent of Buick's turbocharged 231 V6 introduced in 1978 on the Century/Regal intermediates and the full-sized LeSabre Sport Coupe and then the newly introduced front drive Riviera in 1979 for the "S-Type" which later became the T-Type, a moniker that would ultimately replace the GS badge for sporty/performance Buicks in the early 1980s.

The Century GS model returned in 1986 for what was now Buick's front-drive intermediate-sized car (Regal continued as a coupe on the 1978-vintage rear-drive G-body until 1987). The GS was only offered as a two-door coupe and was powered by a fuel-injected 3.8 liter (231 cubic-inch) V6 mated to a four-speed overdrive automatic transmission but with far less horsepower than the rear-drive Regal GN's turbocharged/intercooled version rated at 245 horsepower. This Century GS was a one-year-only offering in 1986 sold alongside the Century T-Type coupe and sedan.

Regal GS / Regal Gran Sport

From 1988 to 2004, there was a Gran Sport version of the Regal. The Gran Sport option generally contained the following items:

  • Cloth bucket seats and center console
  • Black, wide, body side moldings (coupe only)
  • Gran Touring (FE3) suspension - which included faster power steering, and revised springs and struts
  • Front air dam and aero rocker panels (coupe only)
  • 16 inch aluminum wheels
  • Fog lamps (coupe only)
  • Two tone paint (sedan only)
  • Leather steering wheel

Beginning in late 1990, the 3.8L (231 cu in) Series I V6 producing Script error: No such module "convert". was available. The 1997-2004 body style featured a Script error: No such module "convert". 3.8L Series II supercharged V6.

On January 7, 2009, General Motors confirmed it would offer its 2011 Buick Regal GS with a Script error: No such module "convert". Script error: No such module "convert". turbocharged 4-cylinder Ecotec engine, and a six-speed manual transmission. This model will be based on the Opel Insignia OPC (Opel Performance Center).

The GS California

Buick touted the California as "The Distinctive Personal Car for Americana on the GO", using the Skylark platform. The merchandising creation of the West Coast's Mickey Garrett, the California GS became one of Buick's entries into what is now often known as a junior musclecar. The intent of these autos were to provide the visual impact of the era's supercars with the low maintenance and price of a more economical car, while maintaining reasonable performance levels. When reviewed with these thoughts in mind the California GS delivered quite nicely. They were fitted with the small block GS drivetrain and the exterior received the full treatment including vinyl top, chrome moulding package, GS emblems, and special California scripts. This marketing approach was also used in Colorado, using the "Colorado" name instead of "California".

1967 was the maiden year for the California GS. It was available in California only and was not advertised nationally by Buick. Built on the thin-pillar coupe chassis it came equipped with the 340 ci/260 hp engine and Super Turbine 300 transmission. Bench seats were standard and accessories were kept to a minimum to help keep the price down. Car Life tested one in their June issue and ran the 1/4 in 16.7 seconds at 81 mph, they also recorded a top speed of 105 mph. The article contains a lengthy description of the car and how it performed during testing, it is a must read for anyone interested in learning more about the '67 California GS.

Mid year 1968 saw the official introduction of the California GS, and it is frequently known as a '69 model.[4] Buick asked "Why settle for less when the California GS, built especially for YOU, costs no more?" Exclusively designed for Golden State motorists, Buick advertised the car nationally as a high performance family sports car at an economy car price. Though the car was not included in Buick's yearly catalog it was shown in a two-page black and white fold out brochure. Custom California GS emblems again graced the rear fenders while GS ornamentation could be found in the grille and sail panels. The drivetrain included Buick's new for '68 350-4 V8 with 10.25:1 compression and Rochester (GM) 4GC Quadrajet four-barrel (four-choke) carburetor,[5] producing 280 hp and 375 lb·ft of torque. The two-speed[4] Super Turbine 300 transmission (driving a 3.23:1 rear axle gear, designed for highway cruising)[4] and bench seat interior were again the only choices. Buick also added chrome plated wheels and air cleaner lid to the two-door thin pillar coupe. Tires were Script error: No such module "convert". on Script error: No such module "convert". rims.[4]

1969 was the last year of production for the California GS. The car was for the first time featured in Buick's big brochure. A two-page color picture of the thin pillar coupe and pictures of the again standard bench seat interior were included along with equipment descriptions. Tom McCahill tested the car and recorded a 0-60 time of 9.5 seconds and a top speed of 110 mph. Again the car came with Buick's 280 hp 350-4 engine but now it was mated to the new Turbo 350 transmission. Custom California emblems again graced the rear fenders and the rear marker lights were plain red without Buick's normal 350 or 400 script. Vinyl tops, as with previous years, were standard fare with the California's distinctive GS logo on the sail panel.


  1. ^ Flory, J. "Kelly", Jr. American Cars 1960-1972 (Jefferson, NC: McFarland & Coy, 2004), p.484.
  2. ^ a b Flory, p.641.
  3. ^ a b Flory, p.718.
  4. ^ a b c d Guide to Muscle Cars Magazine, 2/87, p.64.
  5. ^ Guide to Muscle Cars Magazine, 2/87, p.62.

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