Recently I've noticed 1994-97 3.8L owners inquiring about or actually buying a 1993 Mark VIII one piece driveshaft as an upgrade. Little do they know that it won't fit!
So I thought it would be a good idea to pass some information along. The complaint from people is they didn't know that the 3.8L 4R70W car has a driveshaft that's 1.20" shorter than the 4.6L car.
94-97 3.8L 4R70W 57" driveshaft
94-97 4.6L 4R70W 58.20" driveshaft
93-98 Mark VIII 4R70W 58.20" driveshaft
89-95 3.8L M5R2 53.80" driveshaft
89-93 3.8L AOD 57.80" driveshaft
89-93 5.0 AOD 57.80" driveshaft
These specs are from the group purchase Shane (Kodiak Kid) had last year.