What is a 350 bore 20 over?

A "350 bore 20 over" typically refers to a 350 cubic inch engine that has been bored out 20 thousandths of an inch (0.020") larger than its original cylinder diameter. This modification increases the engine's displacement and can enhance performance by allowing for more air and fuel to enter the cylinders. The term is commonly used in automotive and racing contexts, especially for performance tuning and rebuilding engines.