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CATEGORIES (articles) > Engines > Buick > Buick Nailhead V8

Buick Nailhead V8


Like its sister General Motors divisions, Buick produced its own family of V8 engines to replace its straight-8 engines. These engines came in many of the same displacements as those from other divisions, but were entirely different.

Buick/Chevrolet Truck "Nailhead V8"

Buick shared its first V8 with Chevrolet's trucks. This family lasted from 1953 through 1956 in Buick cars and from 1956 through 1959 in Chevrolet trucks. It was an OHV/pushrod engine like the then new Oldsmobile "Rocket V8" engine. This motor became known as the "Nailhead" for its unusual vertical position of its small sized valves -that looked like nails... The Nailhead V8 family employed a camshaft with higher lift and longer duration to offset the smaller sized valves and arguably restrictive intake and exhaust port areas.

264

The 264 in³ (4.3 L) 264 was a direct replacement for the 263 straight-8 in Buick's large cars. It was produced from 1953 through 1956.

322

The larger 322 in³ (5.3 L) 322 was also used by Buick from 1953 through 1956, and was then passed to Chevrolet for use in its trucks through 1959.

Nailhead V8

Buick's second variation of this V8 was also named Nailhead. It was produced from 1957 through 1966.

364

Apparently the smallest displacement Nailhead, the 264, was dropped when Buick introduced its new small displacement V8. Buick, like most of its competitors, continued to expanded their durable V8 motor to larger displacements such as the 364 in³ (6.0 L) 364.

400

The next member of the family was the 401 in³ (6.6 L) 400. This was actually a 401 that had been redesignated a "400" in order to meet GM directives for maximum displacement engines in mid-size cars.

Another Buick "400" engine was a member of the 400/430/455 family and was produced from 1967 to 1969.

401

The 401 in³ (6.6 L) 401 was Buick's muscle car motor of choice, and was found in the company's Skylark Gran Sport and Buick Wildcat, among others. As unlikely as it seems, the air cleaner for the engine is annotated with "Wildcat 375" "Wildcat 410" "Wildcat 445" these inscriptions indicated not the in³ but the ft·lbf. of torque produced by the engine. The "Wildcat 410" was the 2-barrel carburated engine that was standard on the 1962-63 LeSabre. The "Wildcat 375" was a no cost option on the 62-63 LeSabre that had lower compression to run on regular fuel (another Buick V8 had "Wildcat 375" written on its air cleaner but it wasn't a "Nailhead", it was the 4 barrel version of the 66-67 small block Buick 340). The "Wildcat 445" had a single 4 barrel carb. It was the standard engine on the Invicta, 1959-66 Electra, 1962-66 Buick Wildcat, 1963 Riviera and 1965 Riviera (the 64 and 66 Riviera models had a 425 in³ engine with a single 4 barrel carb. named "Wildcat 465" as standard equipment).

In an effort to overcome the "restrictive" exhaust port design, Buick enthusiast drag racers in the sixties adapted superchargers with a custom camshaft to feed intake air in through the exhaust ports and used the larger intake ports for exhaust outlets. Perhaps this feat of ingenuity, and the unusual appearance of the motor modified in this manner, also intimidated rival racers and added to the Nailhead V8 legend that lives upon this page of US auto history.

425

425 in³ (7.0 L) 425 This was the largest version of the "nailhead". It began as an option in 1963 on the Riviera and it was later available on the Wildcat and Electra models too. The 1964 and 1966 Riviera had the 425 engine as standard equipment. 4 barrel carburation was standard on all 425 "Nailheads" that were called "Wildcat 465" and it was possible to order 2 4 barrel carbs on it too. This version was called "Super Wildcat" and it was standard on the 1965 Riviera Gran Sport.

Buick "Small-Block"

In 1961 Buick unveiled an entirely new small V8 engine with aluminum cylinder heads and cylinder block. Lightweight and powerful, the aluminum V8 also spawned a turbocharged version, ( only in the 1963 Oldsmobile Cutlass version), the first ever offered in a passenger car, and became the basis of a highly successful cast iron V6 engine. The all-aluminum engine was dropped after the 1963 model year, but was replaced with a very similar cast-iron engine.

215

See also Rover V8 engine

GM experimented with aluminum engines starting in the early 1950s, and work on a production unit commenced in 1956. Originally intended for 180 in³ (2.9 L) displacement, Buick was designated by GM as the engine design leader, and decided to begin with a larger, 215 in³ (3.5 L) size, which was deemed ideal for the new "senior compact cars" introduced for the 1961 model year. This group of cars was commonly called the BOP group or A-bodies.

The 215 had a 4.24 in (107.7 mm) bore spacing, a bore of 3.5 in (88.9 mm), and a stroke of 2.8 in (71.1 mm), for an actual displacement of 3533 cc. The engine was the lightest mass-production V8 in the world, with a dry weight of only 318 lb (144 kg). It was standard equipment in the 1961 Buick Special.

Oldsmobile and Pontiac also used the all-aluminum 215 on its mid-sized cars, the Oldsmobile F-85 and Pontiac Tempest. However the Oldsmobile version of this engine, although sharing the same basic architecture, had cylinder heads designed by Oldsmobile engineers, and was produced on a separate assembly line. Among the differences between the Oldsmobile and Buick versions, it was somewhat heavier, at 350 lb (159 kg). The design differences were in the cylinder heads: Buick used a 4-bolt pattern around each cylinder where Oldsmobile went to a 5-bolt pattern. The 5th bolt was added to the intake manifold side of the head, one extra bolt for each cylinder. This was supposed to alleviate the head-warping problems that came about on the higher compression ratio versions.

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 4600 rpm. 220 ft·lbf (298 N·m) of torque was produced at 2400 rpm with a Rochester 2GC two-barrel carburetor and 8.8:1 compression ratio. A mid-year introduction was the Buick Special Skylark version, which had 10.25:1 compression and a four-barrel carburetor, raising output to 185 hp (138 kW) at 4800 rpm and 230 ft·lbf (312 N·m) at 2800 rpm.

For 1962, the four-barrel engine increased compression ratio to 11.0:1, raising it to 190 hp (142 kW) at 4800 rpm and 235 ft·lbf (319 N·m) at 3000 rpm. The two-barrel engine was unchanged. For 1963 the four-barrel was bumped to an even 200 hp (149 kW) at 5000 rpm and 240 ft·lbf (325 N·m) at 3200 rpm, a respectable 0.93 hp/in³ (56.6 hp/liter).

Unfortunately, the great expense of the aluminum engine led to its cancellation after the 1963 model year. The engine had an abnormally high scrap ratio due to hidden block-casting porosity problems, which caused serious oil leaks. Another problem was clogged radiators from antifreeze mixtures incompatible with aluminum. It was said that one of the major problems was because they had to make extensive use of air gaging to check for casting leaks during the manufacturing process, and not being able 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. Casting sealing technology was not advanced enough at that time to prevent the high scrap rates.

Although dropped by GM in 1963, in January 1965 the tooling for the aluminum engine was sold to Britain's Rover Group to become the Rover V8 engine, which would remain in use for more than 35 years. GM tried to buy it back later on, but Rover declined, instead offering to sell engines back to GM. GM refused this offer.

300

In 1964 Buick replaced the 215 with an iron-block engine of very similar architecture. The new engine had a bore of 3.75 in (95.5 mm) and a stroke of 3.40 in (86.4 mm) for a displacement of 300.4 cu. in. (4.9 L). 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 @ 4600 rpm and 310 ft·lbf @ 2400 rpm, and four-barrel form, with 11.0:1 compression, making 250 hp @ 4800 rpm and 335 ft·lbf @ 3000 rpm.

For 1965 the 300 switched to a 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 340 in 1968.

340

The 340 in³ (5.6 L) 340 was a stroked (to 3.85 in/97.8 mm) version of the 300. It had a four-barrel carburetor and 11.0:1 compression, rated at 260 hp @ 4200 rpm and 365 ft·lbf @ 2800 rpm. It replaced the four-barrel 300 for 1966. It was produced only in 1966 and 1967, with the new Buick 350 taking its place after that.

350

Buick adopted the popular 350 in³ (5.7 L) size with their final family of V8s. Although sharing the displacement of the Chevrolet Small-Block engine family, the Buicks were substantially different.

The Buick 350 V8 had a 3.80 in bore (like the 3800) and retained the 3.85 in stroke of the 340. It was introduced in 1968 and produced through 1980.

The major differences of the Buick 350 when compared to other GM V8's are, deep skirt block construction, external oil pump, under square bore sizing, 3.0" crank main journals, and 6.5" connecting rods. Some of the design characteristics of the Buick 350 are found in modern GM engines such as the 231 V6, and Series I, II, and III 3800 V6's.

Buick "Big-Block"

The company introduced a larger engine family to replace the "Nailhead" in 1967 and was produced through 1976.

400

The 399.95 in³ (6.6 L) 400 was produced from 1967 to 1969. This engine had a bore of 4.04 in (102.6 mm) and a stroke of 3.90 in (99.1 mm). It was the only large V8 engine available for the A-body Buicks due to the GM cube limit restriction prior to 1970. Most parts except the pistons interchange with the 430 and 455.

430

The 429.69 in³ (7.0 L) 430 was produced from 1967 to 1969. This engine had a bore of 4.1875 in (106.4 mm) and a stroke of 3.90 in (99.1 mm). This engine was used in B-, C- and E-body (large body) Buicks. Most parts except the pistons interchange with the 400 and 455.

455

Buick 455 V8

The 455.72 in³ (7.5 L) 455 Buick V8 used a 4.312 in bore and 3.90 in stroke. It was produced from 1970 to 1976 and was based on the 400/430 V8. The regular Buick 455 was conservatively rated at 350 hp (261 kW) while the 455 Stage 1 was underrated at 360 hp (269 kW). The regular 455 could produce 410 to 420 hp (306 to 313 kW) while the Stage 1 produced 415 to 425 hp (310 to 317 kW). The hp was somewhat reduced in 1971, mainly due to the reduction in cylinder compression ratio in order to cope with the introduction new federal laws requiring new cars to use unleaded gas in an effort to reduce exhaust emissions, then, on paper, considerably reduced to approximately 250 hp starting in 1972, due to the new measurement of horsepower as SAE Net horsepower rather than a gross horsepower rating. Tightening emissions controls caused the engine to drop in power, a little at a time, through 1976. Most parts except the pistons interchange with the 400 and 430.

Non-Buick V8s powering Buick Vehicles

In the mid-1970s, GM was using powerplants sourced from various GM divisions where the Buick V8 was considered a factory option with the Buick 350 as the sole survivor, or in the worst case, for Buick vehicles where the 400/430/455 big blocks were phased out because of fuel economy/emission requirements.

260

The 260 in³ (4.3 L) 260 was actually an Oldsmobile V8 engine.

301

The 301 in³ (4.9 L) 301 was actually a Pontiac V8 engine.

403

The 403 in³ engine used in Buicks was actually an Oldsmobile V8 engine.




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