the 371 was produced through 1960. Bore was up to and stroke was increased to for . 1959 and 1960 371s used green painted valve covers. 4-barrel models used 9.25:1 compression in 1957 and 10:1 in 1958 for and and and respectively. A 1958 2-barrel version produced and , but had problems with early camshaft failures due to the high preload valve spring forces. Following the Automobile Manufacturer Association ban on factory supported racing, power ratings went down for the 1959 and 1960 88 models: and for 1959 and and for 1960. It was no longer available in cars in 1961. This engine was used in GMC heavy trucks as the "370" of 232 gross HP at 4200 RPM and torque 355 gross lbs-ft at 2600 RPM from 1957 to 1959.It had hardened valve seats and other features for heavy duty usage. Applications: 1957–1960 Oldsmobile 88 1957–1958 Oldsmobile Super 88 1957–1958 Oldsmobile 98 J-2 Golden Rocket Introduced in the middle of the 1957 model year, the 1957 and 1958 J-2 Golden Rocket had three two-barrel (twin choke) carburetors with a vacuum-operated linkage. Only the center carburetor was mechanically connected to the throttle pedal, and it was the only one equipped with a choke. When the center carburetor was opened to 60° or more engine vacuum drawn from the windshield wiper pump would simultaneously open the front and rear carburetors. These carburetors did not open progressively; they were either open or closed. The J-2 engine also had a slightly thinner head gasket, raising compression to 10.0:1. It was advertised with gross power and torque ratings of at 4600 rpm and at 2800 rpm. Oldsmobile charged $83 for the J-2 option with the three-speed manual (or in the 98), $314 dollars with the automatic. In practice, owners who did not regularly drive hard enough to engage the front and rear carburetors experienced problems with the linkage and carburetor throats becoming clogged, and some J-2-equipped cars had the front and rear carburetors removed and blocked off. Moreover, correct tuning was a continual headache. The package was expensive to produce, and Oldsmobile discontinued it after 1958. 394 Bore was up to for the largest first-generation Rocket, the . 394s were produced from 1959–1964 and were available on many Olds models. Most 394s used 2-barrel carburetors, but special high-compression 4-barrel versions were available starting in 1961. Power for the base engine was up to 315