Jaime Hernandez: In 1960 the U.S. Mint struck a Large Date and a Small Date variety for the Lincoln cent. For the Large Date, the 9 digit in the date is higher than that of the Small Date. On the Large Date the top of the 9 digit is significantly higher than the 1 digit in the date. Also, the 6 digit has a larger 6 compared to the Small Date.
Both coins are common in grades of up to MS65 Red. In MS66 Red, they become more difficult to find. It appears that the Small Date is scarcer in MS66 Red condition. However, in MS67 the Large Date appears to be more difficult to find.