Pad is visible just in front of right hand cylinder head.....there will be a alpha numeric sequence that usually starts with F and ends with two or three letters. The letters tell what horsepower, what engine size, what transmission, what induction, and what body the engine was installed into. The casting number only tells what the raw casting was.....like someone said, an 010 casting could be a truck or a Z/28 or something else. The letter code gets really specific.