This is a Genuine GM United Delco Synchronizer hub, it fits all 1962-1967 Chevy GMC 1/2 ton through 1 tons, with factory Muncie 4 speed. This is the 3rd. Group # 4.384, Part # 3787250. These parts can range from 10 to 75 years old and were made to the standards of the year the part was manufactured.