starter swap question ?

it depends.
1. is current starter in car gear reduction?
in 90 some few mustangs got a gear reduction starter. starting in 92 all ford v8s were.
if it is a gear reduction it will take some rewiring.

2. was the van an auto?
if it was an auto it will bolt in and work but may be to physically big to clear the headers if installed

3. w,c,or m 351?
winsor and most clevelands will work but a mod351 has a different pilot hole size.(just remembered no cleveland in 77)