Small block and big block refer to engines, and their main difference is the size of the apparatus. While both of these engines are V8 pushrod variety engines, all of the measurements of their parts are different. These engines were designed and put into action in 1955 with the large block being about 400 cubic inches with its’ contents being more extensive and more spread out, and the small block is about 265 cubic inches and more compact.
Chevrolet uses small block engines in several of its vehicles from the racy Corvette all the way up to their trucks. The big-block was introduced in the late 1950s and was designed for those vehicles that needed more power such as trucks and larger passenger cars.