Dana/Spicer tries to ease identifying 60s (and other axles too) by casting the model number into the axlehousing as shown and stamping the build date and bill of materials number into the axle tube. The bill of materials number can be cross-referenced to a Spicer book that lists all the part numbers and specs for that particular axle. For example, we have the Weatherly Index 094 X510-8 DSD (March, 1990) from Spicer that covers 1967 to 1978. The problem is, not all Dana 60s are actually marked as promised. For example, our '72 Dodge W200's Dana 60 rear has no cast-in model number or stamped bill of materials number.