Since the introduction of the first Buick V-8 engine of 322 cubic inches displacement in 1953, the trend has been toward larger engines. The practical displacement limitation of this design was reached in 1964 with the 425 cubic inch engine. A new engine program was initiated to provide flexibility for meeting the requirements of an expanded line of vehicles and to take advantage of advances in manufacturing technology. Two displacements were selected for Buick's new V-8 engines, 400 cubic inches and 430 cubic inches. Objectives realized: increased breathing potential; smoother, quieter operation; improved durability; and simplification for improved manufacturing and service. The basic engine design included provisions for future requirements as well as provisions for readily adapting to modern combustion systems for exhaust emission control.