Just installed a 4.10 from a 1969 into my 1954 3800 series truck. It was formely 5.14 to 1. It is much more freeway capable now, but am looking for speedometer drive gear to match the new gears!These are direct bolt in to the early trucks.The early 3/4 tons 3600 series were 4.56 ratio and were known as HO-52 the one ton 3800 series were 5.17 and were called HO-72
