For certain model years between 1973 and 2004, the Regal shared bodies and powertrains with the similar Buick Century.
First generation (1973–1977)
Buick had been the first GM division to bring a personal luxury car to market with its full-size 1963 Riviera but was otherwise slow to react to the developing lower-priced mid-size personal luxury market, which Pontiac created with the 1969 Grand Prix and Chevrolet with the Monte Carlo the following year, 1970.
At the same time Oldsmobile added a formal notchback coupe to its intermediate line, the Cutlass Supreme, in 1970 and that model soon became Olds' best selling intermediate. Wanting a model that could be marketed to compete against the Olds Cutlass Supreme as well as the Grand Prix and Monte Carlo, Buick introduced the Regal for 1973, as a top line special coupe in that division's intermediate A-body line, the Century. The year 1973 also marked the introduction of the first major restyling of GM's intermediate A-body design since 1968.
A highly trimmed, notchback coupe, the first Regal shared its front and rear styling with its Century parent with distinctions amounting to differing grilles and taillight lenses. The Regal shared the same "Colonnade" pillared hardtop roofline (a hardtop with center pillar but frameless doors unlike a sedan body) and greenhouse (window area) with the Grand Prix, Monte Carlo and Cutlass Supreme as well as the lower-priced Buick Century Luxus coupe. Like its corporate cousins, the Regal (and Luxus) featured the newly fashionable opera windows, which were small fixed rear-side windows surrounded by sheetmetal, instead of the traditional roll-down windows. Only the Colonnade hardtop coupe was offered in the Regal line in 1973, but a new four-door Colonnade sedan (with six-window-greenhouse and frameless door windows) debuted in 1974 and continued through the 1977 model year. Regal interiors were generally more luxurious than lesser Century models with woodgrain trim on dashboard and door panels, along with door-pull straps and notchback bench seats with center armrests with either cloth, velour or vinyl upholstery. Optionally available throughout the run was a 60/40 split bench seat with armrest. For 1976 and 1977, the Regal coupe was available with the S/R option that included reclining bucket seats with corduroy upholstery. The model lasted five years with minimal changes, although there was a fairly substantial facelift in 1976 (for the coupe only - sedans stayed with original 1973 sheetmetal through 1977), which incorporated the recently legalized square headlights (horizontally-mounted on coupes, and vertically on sedans - much like the mid-1960s Pontiacs). The Regal was most commonly powered by Buick's 350 in³ V8, which was standard equipment on all models in 1973 and 1974 and optional on coupes but remained standard on sedans from 1975 to 1977, and the larger 455 in³ V8 was optional in 1973 and 1974 only. Starting in 1975, Regal coupes came standard with Buick's resurrected 231 cu in (3.8 L) V6 engine previously offered on the Skylark from 1964 to 1967; the engine's tooling had been sold to Kaiser Motors for use in Jeep models (Kaiser was purchased by American Motors in 1970 and Jeep became an AMC division) and sold back to GM by AMC in 1974. In 1975 and 1976, the Century and Regal were the only mid-sized cars in America to offer V6 engines. The bolt pattern for this vehicle is 5x120.7.
The Century designation was quietly dropped from the Regal in 1975.
Second generation (1978–1987)
A downsized Regal appeared for 1978 with Buick's new 196 cu in (3.2 L) V6 engine as standard equipment and a new version of the venerable 231 cu in (3.8 L) V6 as an option (which became standard in 1980). Initially a 3-speed manual transmission was standard but this was later replaced by an automatic. This model lasted 10 years. The base model was equipped with softer riding luxury suspension, and did not offer of a manual transmission in later years.
The 1978 Regal could be equipped with a 3.8 L Turbocharged V-6 engine with automatic transmission. Non-turbo versions were offered with either a 2-bbl or a 4-bbl carburetor. The Buick LeSabre was also available with the turbocharged engine. The only other turbocharged cars available in the U.S. market in 1978 were imports from Saab and the Porsche 930. The Turbo Regal also included a firm handling suspension with larger tires and sport wheels.
A major facelift in 1981 gave the Regal a much more aerodynamic profile, helping make it possible for the car to compete on the NASCAR racing circuit. The sloping hood and nose of the car made it the favorite of several NASCAR teams. Richard Petty drove one to victory in the 1981 Daytona 500, and the car won a majority of the 1981 and 1982 seasons races and won the NASCAR manufacturers title in 1981 and 1982. V8s for street use were still available, but had shrunk to 265 cu in (4.3 L) (1980 and 1981 only, Pontiac built), and the V6 was rapidly gaining popularity. In 1982, a new Century appeared on the front-wheel drive A-body, but the former rear-wheel drive Century sedan and wagon were not discontinued. These models were simply rebadged as Regals, and for the first time the name appeared on a full model lineup. The wagon was discontinued after 1983, and the sedan dropped from the lineup the next year. From 1986 to 1987, the 5.0 L 307 V8 was available as an option. The 3.8 2-bbl V6 was standard. The 200-4R overdrive transmission was an option with either engine.
Grand National, T-Type and GNX
In 1982, the Regal Grand National debuted, which was named for the NASCAR Grand National racing series. Buick had won the Manufacturers Cup in 1981 and 1982, and wanted to capitalize on its success: "What wins on Sunday, sells on Monday". These 1982 cars were not painted black, which may confuse those not familiar with them. All started out as charcoal gray Regals that were shipped off to a subcontractor for finishing.
Originally intended for a run of 100 units, Cars and Concepts of Brighton, Michigan, retrofitted 215 Regals with the GN package. Most obvious was the light silver gray firemist paint added to each side. Red pinstripes and billboard shadow lettering proclaiming "BUICK" were applied. The wheel opening moldings and rocker panel moldings were blacked out using black vinyl tape. Finally, a front air dam and rear spoiler were installed. On the inside, special "Lear-Siegler" seats were installed. These seats are fully adjustable and were covered with silver brandon cloth with black vinyl inserts. The front seat had Buick's "6" emblem embroidered onto them. To finish it off, a special clock delete plate was added to the instrument panel which contained the yellow and orange "6" logo and the words "GRAND NATIONAL BUICK MOTOR DIVISION."
The '82 GN came with a naturally aspirated 4.1 L V6 engine with 125 hp (93 kW) at 4000 rpm and 205 lb·ft (278 N·m) of torque at 2000 rpm. Of the 215 Regal Grand Nationals produced in 1982, a handful were based on the Buick Regal Sport Coupe package with the turbocharged 3.8 V6 engine with 175 hp (130 kW) at 4000 rpm and 275 lb·ft (373 N·m) of torque at 2600 rpm. There were only 2022 Sport Coupes produced in 1982, and the number of cars with both the GN and Sport Coupe packages is estimated to be less than 50.
For 1983, there was no Grand National. The Sport Coupe model was renamed the T-Type; 3732 were produced (190 hp (140 kW) at 1600 rpm and 280 lb·ft (380 N·m) of torque at 2400 rpm). The T-Type had been used on other Buicks, starting with the Riviera in 1981 (in 1979 and 1980, it was the S Type). The 1983 Regal T-Type featured tube headers, Hydro-Boost II brakes, 200-4R 4-speed overdrive trans and 3.42 rear axle (7.5").
In 1984 the Grand National returned in all black paint. The turbocharged 3.8 L became standard and was refined with sequential fuel injection, distributor-less computer controlled ignition, and boasted 200 hp (150 kW) at 4400 rpm and 300 lb·ft (407 N·m) of torque at 2400 rpm. Only 5,204 Turbo Regals were produced that year, only 2000 of which were Grand Nationals. Because this was the first year production of the computer controlled Sequential Fuel Injection and Distributor-less ignition, this is often considered the year/model that started the development of the legendary intercooled Grand Nationals. The performance of this package was well ahead of its time and the “Little V6” easily matched that of the bigger V8’s. Quarter mile (~400 m) performance was listed at 15.9 seconds at stock boost levels of 10 psi (0.69 bar), while for the same year, the Chevrolet Camaro was listed at 17.0 and the Chevrolet Corvette at 15.1 seconds. Soon, performance enthusiasts determined the modifications that worked and the Grand Nationals easily broke into the 13 second territory. All Grand Nationals for this year had the Lear Siegler-made cloth/leather interior which was only available for this year. An estimated 425 of the 1984 Grand Nationals were produced with the T-Top option which makes these one of the rarest of the Grand Nationals.
In 1986, a modified engine design with intercooling boosted the performance even further; in 1987 it reached 245 hp (183 kW) and 355 lb·ft (481 N·m) of torque. Buick dropped the T-Type package for Regal in 1987. There were only 7,896 Turbo Regals produced in 1986. In 1987, when Turbo Regals reached their peak in popularity, a total of 27,590 Turbo Regals were produced through December, with those models produced between September and December of that year window stickered as "1987½ Buick Grand National" vehicles.
In 1987, a lightweight WE4 (Turbo T) option was offered. Only 1,547 of this variant were produced. They were painted black and treated to the same blackout package as the Grand National, including bumpers, grille, headlight and taillight trim. The differences between a WE4 and the Grand National were the interior trim package, wheels, exterior badging, aluminum bumper supports, and aluminum rear brake drums as opposed to the Grand National's cast iron. The rear spoiler was only available as a dealer installed option. 1987 was the only year that the LC2 Turbo option was available on any Regal, making it possible to even see a Limited with a vinyl landau roof and a power bulge turbo hood. Turbo Regal Limiteds were one of the rarest models of Turbo Regals produced second only to the GNX at 1,035 Turbo Limiteds. Turbo Regal Limiteds could be ordered with many options with most having chrome external trim but for $35 could have been built with the full black-out trim option making them extremely rare. Limiteds were treated to a very luxurious interior with plush carpeting and optional bench pillow seats and a column shift. The 1987 model would be the end of the manufacture of the RWD "G-Body" Regal, but GM had to extend the build of the Grand National to meet customer demand.
For the final year, 1987, Buick introduced the GNX at $29,900. Produced by McLaren Performance Technologies/ASC, Buick underrated the GNX at 276 hp (206 kW) and a very substantial 360 lb·ft (488 N·m) of torque. This was created to be the "Grand National to end all Grand Nationals." Changes made included a special Garrett T-3 turbocharger with a ceramic-impeller blowing through a more efficient and significantly larger capacity intercooler with a "CERMATEL (Ceramic/Aluminum) coated" pipe connecting the intercooler to the engine.
A GNX specific EEPROM, low-restriction exhaust with dual mufflers, reprogrammed Turbo Hydramatic 200-4R transmission with a custom torque converter and transmission cooler, and unique differential cover/panhard bar included more of the performance modifications. Exterior styling changes include vents located on each front fender, 16 inch black mesh style wheels with VR-speed rated tires, and deletion of the hood and fender emblems. The interior changes of the GNX included a serial number on the dash plaque and a revised instrument cluster providing analog Stewart-Warner gauges, including an analog turbo boost gauge. Performance was measured with a quarter mile time of 13.5 seconds at 102 mph (164 km/h) and a 0-60 mph (97 km/h) time of 4.7 seconds.
GNX #001 is the 1986 prototype currently owned by Buick and sometimes makes appearances at car shows around the US. The GNX had a ladder bar that ran from the midsection of the car to the rear axle, so as to increase traction. This is also the reason why a GNX will actually lift the rear end up when the car is about to launch heavily.