To get the best information, take the transmission to a transmission shop and ask them. This trans may be a truck type and you may find that the internal gearing is not sutible for a smaller vehicle application.
For a crossmember, look at a 1971 Mustang as that is the last year of big blocks, and assume that the drive shaft length will need to be altered, which is a common practice.
Tag info: (based on the 1965-72 parts book)
PJD - transmission type
W2 - possible additional identification
D21 - service identification code
D5UP TA - transmission part number (a 1975 design)
022312 - build date and shift code or serial number (depends on type)
Jim