My 95 E150 had a reverse pump, and all others (E & F series) I've seen were as well. Could be the 90 was at or near the switch in front accessory drive. The F150's had the 302 and 351 till 96 and a few stragglers into 97. The E series were into 97's for sure with both. The full size Ford/Lincoln /Merc's had std rotation stuff till the end in 91.