# Buick V8 engine

The Buick V8 is a family of V8 engines produced by the Buick division of General Motors (GM) between 1953 and 1981. All were 90° water-cooled V8 OHV pushrod engines, and all were naturally aspirated except one turbocharged version of the 215.
The Buick V8 family can be divided into two sizes, big-blocks and small-blocks (block size classification refers to the engine block's bore spacing and external dimensions, not displacement). All 1953–1966 Buick V8s and the 1967–1976 "big-block" engines shared a 4.75 in (121 mm) bore spacing. The small-block was produced from 1961 to 1981.
Some Buick V8s, such as the 350, 400, and 455, have the same displacements as V8s of other GM divisions, but they are entirely different designs. Buick Nailhead V8s can be distinguished by the top surfaces of their valve covers being horizontal (parallel to the ground). Later Buick small and big block V8s have a front-mounted distributor tilted to the drivers side (like Cadillacs), but siamesed center exhaust ports (unlike Cadillacs).

## First-generation Nailhead

Buick's first generation V8 was offered from 1953 through 1956; it replaced the Buick straight-eight. While officially called the "Fireball V8" by Buick, it became known by enthusiasts as the "Nailhead" for the unusual vertical alignment of its small-sized valves (Originally it was known to hot-rodders as the "nail valve", because the engine's small heads contained valves with long stems, which made them look like nails.)
During this era, Buick ranked smoothness above most other marketing objectives, and the Dynaflow transmission's non-shifting design was demonstrably smoother than the other rough shifting automatics then available. With the Dynaflow, a high torque engine was needed to provide adequate acceleration, so that's what the Nailhead was designed to deliver.
Both the intake and exhaust valves were on the intake manifold side of a "pent-roof combustion chamber". To offset restrictive port diameters and the smaller-sized valves [1.75 in (44 mm) intake, 1.25 in (32 mm) exhaust], the Nailhead V8s used a camshaft with greater lift and duration. The small-diameter intake runners allowed these engines to develop high torque, with many exceeding 1 ft-lb/cu in (exceptional for the time).
First-generation Nailheads were painted "Late" Buick Green (also called Apple Green, used from 1953 to 1965).

### 264

The 264 cu in (4.3 L) produced in 1954 and 1955 was a direct replacement for the 263 straight-eight and the only engine available in Buick's economy "Special" series vehicles. It was the smallest displacement Nailhead, sharing stroke and deck height with the 322, but having its own smaller bore 3.625 in (92.1 mm).

### 322

The larger 322 cu in (5.3 L) was the original Nailhead, used by Buick from 1953 through 1956 in the Roadmaster, Super, and Century models, and the Special in 1956. It has a bore and stroke of 4 in × 3.2 in (101.6 mm × 81.3 mm).
The 322 was also used in the 1956 through 1957 10,000-Series conventional-cab Chevrolet heavy duty trucks labeled as the Loadmaster.

## Second-generation Nailhead

Buick's second variation of the "Nailhead" was produced from 1957–1966. The "Fireball" name was dropped after 1957, but the 364 was very briefly called the "B-12000", referring to the 12,000 foot pounds generated by each piston. Second generation Nailheads were painted "Late" Buick Green, with the exception of those installed in the 1963 Riviera, which were silver, and the 1966 Riviera, which were red.

### 364

Buick, like most of its competitors, continued to expand their V8 engine to larger displacements. The 364 cu in (6.0 L) was introduced in 1957 and produced through 1961, with a 4.125 by 3.4 inches (104.8 mm × 86.4 mm) (bore by stroke). The Special series cars came standard with the 250 hp (186 kW) two-barrel carburetor version, where all other models got the 300 hp (224 kW) four-barrel engine.

### 401 (400)

The 364 was enlarged to 401.0 cu in (6.6 L; 6,572 cc) and produced from 1959 to 1966. Bore and stroke were enlarged to 4.1875 by 3.64 inches (106.36 mm × 92.46 mm) respectively. Originally labelled a 401, it was later redesignated "400" (with no change to displacement) to meet 1960s GM directives for maximum allowable engine displacements in mid-size cars.
The 401/400 became Buick's muscle car powerplant of choice, used in the company's Skylark Gran Sport, Buick Sport Wagon and Buick Wildcat models, among others. The engine was variously designated the Wildcat 375, Wildcat 410, and Wildcat 445 depending on the torque each version produced. The Wildcat 410 was the two-barrel carbureted engine, standard on the 1962-63 LeSabre. The Wildcat 375 was a no-cost option for the 1962-63 LeSabre that used a lower compression ratio to run on lower-octane fuel. The various Wildcat engines had decals on their air cleaners indicating their version; however, the four-barrel edition of the 1966-67 small-block Buick 340 V8 was also labeled Wildcat 375 on its air cleaner, but was not a Nailhead.
The Wildcat 445, with a single four-barrel carburetor, was the standard engine in the Invicta, 1959-1966 Electra, 1962–1966 Buick Wildcat, 1963 Riviera, and 1965 Riviera (the 1964 and 1966 Riviera models used the 425 with a single four-barrel carburetor, labeled Wildcat 465, as standard equipment).
In an effort to overcome the restrictive exhaust-port design of the Nailhead, Buick drag racing enthusiasts in the 1960s adapted superchargers with a custom camshaft to feed intake air in through the exhaust ports; the larger intake ports became the exhaust outlets.

### 425

The 425 cu in (7.0 L) was produced from 1963 to 1966. Its bore and stroke measured 4.3125 by 3.64 inches (109.54 mm × 92.46 mm). The largest-displacement version of the Nailhead, it began as an option on the 1963 Riviera, and was later available on the Wildcat and Electra models. The 1964 and 1966 Rivieras used the 425 engine as standard equipment. Mounted on a trolley, Buick 425s were also used as starter motors for the SR-71 Blackbird supersonic jet.
Four-barrel carburetion was standard on the basic 425, called the Wildcat 465 for the torque (as measured in lb-ft) it developed. The Super Wildcat (Regular Production Option {RPO}-coded Y48) was available on the 1964 Riviera as a factory option (2,122 produced), 1964 Electras (any model, production numbers unknown), 1965 Riviera Gran Sport and 1966 Wildcat GS, which included two four-barrel carburetors and matching intake manifold. Coded "MW", these parts were delivered in the car's trunk for dealer installation. Toward the end of the 1966 model year, around May 1966, Buick offered the Super Wildcat 465 with factory-installed dual four-barrel Carter AFB carburetors as an "MZ" option. Only 179 of the 1966 Riviera GS cars were built with the MZ package.

## Big-block

Buick introduced its "Big Block" V8 in 1967 to replace the largest displacement Nailheads. It retained the 4.75 in (120.7 mm) cylinder bore spacing and was produced in three displacements: 400, 430, and 455 cubic inches. Production continued through 1976.

### 400

The 399.95 cu in (6,554 cc) big-block V8 was produced from 1967-1969. This engine has a bore and a stroke of 4.04 in × 3.9 in (102.6 mm × 99.1 mm). It was the only large V8 engine available for the intermediate-sized A-body Buicks due to the GM cubic inch limit restriction in effect through 1970. Most parts except the pistons interchange with the 430 and 455. This 400 engine had the distributor towards the front of the engine, as opposed to the 401/400 nailhead, which had its near the firewall.

### 430

The 430-cubic-inch (7.0 L) was only produced from 1967 until 1969. This engine had a bore and a stroke of 4.1875 in × 3.9 in (106.36 mm × 99.06 mm). The 430 four-barrel engine was rated at 360 hp (268 kW) and 475 lb⋅ft (644 N⋅m) of torque. This engine was used in large B-, C- and E-body Buicks. Most parts except the pistons interchange with the 400 and 455.
Applications:
* 1967-1969 Buick Electra
* 1967-1969 Buick Riviera
* 1967-1969 Buick Wildcat

### 455

The 400-based 455 was produced from 1970–1976, with a bore x stroke of 4.31 in × 3.9 in (109.5 mm × 99.1 mm) for an overall displacement of 455.2 cu in (7.5 L; 7,459 cc). Most parts (except pistons and heads) interchange between the 400 and the 430. The base model was rated at 350 hp (261 kW), while the 455 Stage 1 equipped with a single 4-barrel Rochester Quadrajet carburetor was rated at 360 hp (268 kW) at 4600 rpm. The regular 455 produced a rated 510 lb⋅ft (691 N⋅m) of torque at 2,800 rpm, more than any other muscle car engine. The horsepower was somewhat reduced in 1971 mainly due to the reduction in cylinder compression ratio, a change which was mandated by GM in order to cope with the introduction of new federal laws which would require new cars to use low octane gasoline in an effort to reduce exhaust emissions. Then, starting in 1972, the horsepower rating on paper would be reduced again due to a shift from SAE gross to SAE net, down to approximately 250 hp (186 kW). Unleaded gasoline and catalytic converters came into play in 1975 for all US manufactured cars. Tightening emissions controls would cause the engine to drop in power still further, a little at a time, through 1976.
The 455 was one of the first "thin-wall casting" engine blocks at GM, and because of this advance in production technology, it weighs significantly less than other engines of comparable size (for example, 150 lb (68 kg) less than a Chevrolet 454 and only 25 lb (11 kg) more than a Chevrolet 350).
Applications:
* 1970-1976 Buick Electra
* 1970-1976 Buick Estate
* 1970-1976 Buick LeSabre
* 1970-1976 Buick Riviera
* 1970-1972 Buick Skylark
* 1970 Buick Wildcat
* 1971-1973 Buick Centurion
* 1973-1974 Buick Century
* 1973-1974 Buick Gran Sport
* 1973-1974 Buick Regal

## Small-block

Buick introduced a "small block" V8 in 1961 with a 4.24 in (107.7 mm) cylinder bore spacing; it was produced in four displacements, 215, 300, 340, and 350. This design also became the basis of a highly successful cast iron V6 engine, the Fireball. Design features include an external oil pump, a forward-mounted distributor, and an integrated aluminum timing cover which incorporates the oil pump mechanisms, leaving the oil filter exposed to oncoming air for added cooling.
With the exception of the silver 1964 300, Buick small-blocks were painted "Late" Buick Green through 1966. Buick engines were painted red from 1967-1974, medium metallic blue from 1975-1977, and light blue from 1978-1982.
The small-block was originally produced as an industry-first all-aluminum engine. Alas, after 3 years of production, persisting cylinder liner issues, trumped with new and cheaper thin-wall iron casting techniques, pushed a change to an iron block.

### 215

    See also Rover V8 engine
GM experimented with aluminum engines starting in the early 1950s, when Aluminum Company of America (ALCOA) was pushing all automakers to use more aluminum. An early-development supercharged version of the 215-cubic-inch (3.5 L) V8 was used in the 1951 Le Sabre concept car, and the 1953 Buick Roadmaster concept car.
GM designated Buick as engine design leader, and work on a production unit commenced in 1956. Originally intended for 180-cubic-inch (2.9 L) displacement, Buick decided on a larger, 215-cubic-inch (3.5 L) size, deemed ideal for the new Y-body cars introduced for 1961, like the Skylark.
Known as the Buick Fireball, the 215 had a bore and a stroke of 3.5 in × 2.8 in (88.9 mm × 71.1 mm), for an actual displacement of 215.51 cu in (3,532 cc). With its aluminum cylinder heads and cylinder block, at the time it was the lightest mass-production V8 in the world, with a dry weight of only 318 lb (144 kg). Measuring 28 in (71 cm) long, 26 in (66 cm) wide, and 27 in (69 cm) high (same as the small-block Chevy), it became standard equipment in the 1961 Buick Special.
At introduction, Buick's 215 was rated 150 hp (112 kW) at 4400 rpm. This was raised soon after introduction to 155 hp (116 kW) at 4,600 rpm. 220 lb⋅ft (298 N⋅m) of torque was produced at 2,400 rpm with a Rochester 2GC (2 Jet) two-barrel carburetor and 8.8:1 compression ratio. A mid-year introduction was the Buick Special Skylark version, which had 10.0:1 compression and a four-barrel carburetor, raising output to 185 hp (138 kW) at 4,800 rpm and 230 lb⋅ft (312 N⋅m) at 2,800 rpm.
For 1962, the four-barrel-equipped engine's compression ratio was increased to 10.25:1 and horsepower to 190 hp (142 kW) at 4,800 rpm and 235 lb⋅ft (319 N⋅m) at 3,000 rpm. The two-barrel engine was unchanged. For 1963, the four-barrel was bumped to 11.0:1 compression and an even 200 hp (149 kW) at 5,000 rpm and 240 lb⋅ft (325 N⋅m) at 3,200 rpm, 0.93 hp (0.7 kW)/cu in. The higher output "Power Pack" was equipped with higher lift camshaft .0.518" intake/ 0.523" exhaust with increased duration 305/310 and required 99 research octane fuel.

#### Pontiac usage

Pontiac used the Buick version of the 215 in its Y-body cars, the Tempest and LeMans. At that time the engine was closely associated with the Buick brand, and Pontiac sold few cars with it, using it only in 1961 and 1962.

#### Oldsmobile version

Although sharing basic architecture with the Buick, Oldsmobile developed its own all-aluminum 215, the "Rockette V8", to install in its F-85 Cutlass Y-body. Its angled valve covers were designed by Oldsmobile engineers to look like a traditional Olds V8.
Olds also released a turbocharged version, the 215 hp (160 kW) Turbo-Rocket, in its 1962–63 Oldsmobile Jetfire. Together with Chevrolet's turbocharged 1962 Corvair Spyder, these were the first turbochargers ever offered in passenger cars.
Produced on a separate assembly line, the Olds 215 was somewhat heavier at 350 lb (160 kg). Intended to alleviate a head-warping problem on high-compression versions, Oldsmobile added a sixth head bolt on the intake manifold side. This meant that the five-bolt Buick heads would fit on Oldsmobile blocks, but not vice versa. The Oldsmobile used wedge-shaped/quench combustion chambers/pistons that allowed larger valves, while the Buick had a 37-cc wedge combustion chamber and used "dished head" pistons. Altering the compression ratio on the Oldsmobile 215 required changing the heads, but on a Buick 215, only the pistons were changed, which was less expensive and simpler.

#### Discontinuation

Casting-sealing technology was not advanced enough at that time, and hidden porosity problems caused serious oil leaks, producing an abnormally high scrap ratio. The factory had to make extensive use of air gauging for leak checks, and was unable to detect leaks on blocks that were as much as 95% complete. This raised the cost of complete engines to more than that of a comparable all cast-iron engine, so aluminum blocks were cancelled after the 1963 model year. Another problem was clogged radiators from antifreeze mixtures incompatible with aluminum.

#### Racing

The 215's very high power-to-weight ratio made it immediately interesting for automobile and boat racing. Mickey Thompson entered a stock-block 215-powered car in the 1962 Indianapolis 500, the first stock-block engine since 1946 and the only non-Offenhauser-powered entry in the race. Rookie driver Dan Gurney qualified eighth and raced well for 92 laps before retiring with transmission problems.
Surplus engine blocks of the Oldsmobile F85 version formed the basis of the Australian Formula One Repco V8 used by Brabham to win the 1966 Formula One world championship, although only the earliest engines had any Oldsmobile components. The majority of Repco RB620 engines were cast and built in-house at Repco.

#### Sale to Rover

Rights to these engines were purchased by the British Rover Company and used in the 1967 Rover P5B that replaced the 3 L straight six Rover engined P5. Throughout the years, the Rover Company (which became part of British Leyland in 1968), and its successor companies constantly improved the engine making it much stronger and more reliable. Capacities ranged from 3.5 to 5.0 L (215 to 307 cu in). This engine was used for V8 versions of the MGB GT known as the GTV8. Rover also used the engine in the 1970 Range Rover. Morgan used the Rover version in its Plus 8. American 215s have also been engine swapped into countless other platforms, especially Chevrolet Vegas and later British cars including the MG RV8 in the 1990s, Triumph TR8, and various sports sedans and sports cars by the MG Rover Group and specialist manufacturers such as TVR. The engine remains well-supported by enthusiast clubs, specialist parts suppliers, and by shops that specialize in conversions and tuning.

### 300

In 1964, Buick replaced the 215 with an iron-block engine of very similar architecture. The new "small block" engine had a bore of 3.75 in (95.3 mm) and a stroke of 3.4 in (86.4 mm) for a displacement of 300.4 cu in (4.9 L; 4,923 cc). It retained the aluminum cylinder heads, intake manifold, and accessories of the 215 for a dry weight of 405 lb (184 kg). The 300 was offered in two-barrel form, with 9.0:1 compression, making 210 hp (157 kW) at 4600 rpm and 310 lb⋅ft (420 N⋅m) at 2400 rpm, and four-barrel form, with 11.0:1 compression, making 250 hp (186 kW) at 4800 rpm and 355 lb⋅ft (481 N⋅m) at 3000 rpm.
For 1965, the 300 switched to cast-iron heads, raising dry weight to 467 lb (212 kg), still quite light for a V8 engine of its era. The four-barrel option was cancelled for 1966, and the 300 was replaced entirely by the 350 in 1968.
In 1964, while nearly all Buick engines were painted "Buick Late Green", the 300 V8s were painted silver instead. In 1966 Buick engines switched to "Buick Late Red", but until 1967 at least, the 300 V8 (and the 225) were still painted Buick Late Green. The Apollo 5000 GT sports car, (also sold as the Vetta Ventura) used this engine.

### 340

In 1966, the 300's stroke was increased to 3.85 in (97.8 mm) in a raised block to create the 340, displacing 340.2 cu in (5.6 L; 5,574 cc), as a replacement for the four-barrel-carbureted 300. The taller deck (raised by 0.5625 in (14.3 mm) compared to the 215/300's) meant the intake manifold was of a new design to bolt to the otherwise interchangeable cylinder heads.
It was offered with two- or four-barrel carburetion, the two-barrel with a 9.0:1 compression rated at 220 hp (164 kW) at 4,000 rpm and 340 lb⋅ft (461 N⋅m) at 2,400 rpm, and the four barrel with 10.25:1 compression, rated at 260 hp (194 kW) at 4,000 rpm and 375 lb⋅ft (508 N⋅m) at 2,800 rpm. It was only produced through 1967, being replaced by the new small block 350 cu in (5.7 L) in 1968.

### 350

Buick adopted the popular 350 size in 1968 for their final family of V8 engines, which was produced through 1980. Although it shared the displacement of the other GM small blocks, including the Chevrolet 350, Oldsmobile 350, and Pontiac 350, the Buick blocks were of a substantially different proprietary company design. The Buick 350 featured the same 3.8 in (96.5 mm) bore as the 231 cu in (3.8 L) version of the Buick 90° V6 and retained the 3.85 in (97.8 mm) stroke of the previous 340 cu in (5.6 L) V8. The exact displacement is 349.31 cu in (5,724 cc).
The major differences of the 350 in comparison to other GM V8s are Buick's "deep-skirt" engine block construction, the use of cast iron with increased nickel content, under-square cylinder bore sizing, 3 in (76.2 mm) crankshaft main journals, and 6.385 in (162.2 mm) connecting rods. Of all the GM "350s", the Buick has the longest piston stroke. This design characteristic made the engine significantly wider than the others — essentially the same as the Buick big-blocks, which have the shortest stroke of the GM big-blocks. The engine garnered a reputation as rugged and durable, and some of its design characteristics are found in other Buick-designed GM engines, such as the 231 cu in (3.8 L) V6 and its 3800 descendants.
The 350 was used by Kaiser-Jeep and AMC Jeep in the Jeep Gladiator and Wagoneer models from 1968–71; in these applications, the engine was billed as the Dauntless V8.
* 1968-1972 Buick Skylark
* 1968-1972 Buick Sport Wagon
* 1968-1971 Jeep Wagoneer
* 1968-1971 Jeep Gladiator
* 1971-1973 Buick Centurion
* 1971-1980 Buick Electra
* 1971-1980 Buick LeSabre
* 1973-1975 Buick Apollo
* 1973-1977 Buick Century
* 1973-1977 Buick Regal
* 1975 Pontiac Ventura
* 1975-1979 Buick Skylark
* 1977-1980 Buick Estate
* 1977-1978 Buick Riviera

## Other GM V8s used in Buicks

In the mid-1970s, Buick's 455 big block became unable to meet fuel economy/emission requirements and was phased out, with the Buick 350 remaining as a factory option until 1980. In their place a variety of other GM divisions' V8s were offered, both as standard equipment and factory options. These included:

### Oldsmobile 260

The 260 cu in (4.3 L) was an Oldsmobile V8 engine shared with Buick:
* 1975–1977 Buick Skylark

### Pontiac 301

The 301 cu in (4.9 L) was a Pontiac V8 engine shared with Buick.

### Chevrolet 305

The 305 cu in (5.0 L) was a Chevrolet V8 engine shared with Buick:
* 1978–1987 Buick Regal
* 1975–1979 Buick Skylark

### Oldsmobile 307

The 307 cu in (5.0 L) was an Oldsmobile V8 engine shared with Buick:
* 1980–1985 Buick Lesabre
* 1980–1984 Buick Electra
* 1980–1985 Buick Riviera
* 1980–1990 Buick Estate Wagon
* 1986–1987 Buick Regal

### Oldsmobile 403

The 403 cu in (6.6 L) was an Oldsmobile V8 engine shared with Buick:
* 1977 Buick Century estate
* 1977–1979 Buick Riviera
* 1977–1979 Buick Electra
* 1977–1979 Buick Estate Wagon
* 1977–1979 Buick LeSabre