Under the distributor ? Normally on the 440's there a flat pad on the drivers side with numbers on it . The B block's ( 383/400 ) have numbers under the distributor not the RB's . I know some blocks have other numbers stamped on them to tell you about the motor but I can't think of were those stampings are at the moment . They tell you things like if it's a stock bore and weather it runs on low or high octane and such .