only engine available for the economy "Special" series during its run. The smallest displacement Nailhead, it is a small-bore version of the 322, sharing stroke and deck height, but having its own bore. 322 The larger 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 . The 322 was also used in the 1956 through 1957 10,000-Series conventional-cab Chevrolet heavy duty trucks labeled as the Loadmaster. Buick "Nailhead" V8 (second generation) Buick's second variation of the nicknamed "Nailhead" was produced from 1957–1966, and the "Fireball" name was no longer used starting in 1958, and was very briefly called the "B-12000" referring to the 12,000 foot pounds generated by each piston. 364 The 364 was introduced in 1957 and produced through 1961. The Special came standard with two-barrel carburetor and , where all others had the four-barrel, engine. Buick, like most of its competitors, continued to expand their durable V8 engine to larger displacements, such as the (bore by stroke) . 401 (400) The 364 was enlarged to and produced from 1959 to 1966. Originally a 401, it was later redesignated a 400 to meet 1960s GM directives for maximum displacement engines in mid-size cars. The 401/400 became Buick's full-sized and later intermediate 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