The classic big block stock engines could deliver a lot of power. Not nearly as much per cubic inch as the modern engines, of course, but they had a lot of cubic inches. Unfortunately, because they were massed produced, they were not made to exacting tolerance. Slight variations in cylinder compression, cylinder alignment and other factors rob these engines of as much as 20% of their power. Blocking is a technique to realign and standardize these parameters and allow the engine to reach its fullest potential. Look under "Blocking" to find out more.