The 400 CID Chevy small block engine was produced from 1970 until 1980 and was the largest displacement engine made in that platform. It was intended as a low performance, high-torque engine primarily used in Chevy’s heavier passenger cars and light-duty trucks. The general design was the same as earlier small block Chevrolet engines and incorporated many similar external features and dimensions while being internally different. The 400 has gained notoriety – with modifications – as a powerful performance engine.
The 400 CID small block engine kept the same external dimensions as the other small block engines, but increased its displacement through internal modifications. The engine shares the same length, width and height as other SBCs at approximately 28 by 26 by 27 inches respectively.