I had an 87 4x4 with I6 and 4spd manual in high school. I got rid of it with 280k only cause I found a nice price on a 250 diesel. Both were good trucks and went over 300k.
My dad just retired this past year but he sold his work van '00 ford e-250 5.4 w/ 750k miles (org motor/trans, never apart for major repairs)
Always used Lucas Oil additive.