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 was only produced from 1967 until 1969. This engine had a bore and a stroke of . The 430 four-barrel engine was rated at and 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 was produced from 1970–1976, with a bore x stroke of . Most parts (except pistons and heads) interchange between the 400 and the 430. The base model was rated at , while the 455 Stage 1 equipped with a single 4-barrel Rochester Quadrajet carburetor was rated at at 4600 rpm. The regular 455 produced a rated 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 . 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, less than a Chevrolet 454 and only 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 GM V8s In the mid-1970s Buick's 400/430/455 big blocks became unable to meet fuel economy/emission requirements and were phased out, with