You "can" run an automatic ECU in a manual vehicle, but you will have the CEL on all the time because there are no hook ups for the torque converter lockup or 3/4 shift solenoid, so computer thinks there is a problem.
Idle will also be high, 750-800, because that is the programmed idle for automatics.
Any PCM from 1990-1994 Ranger 4.0l from 49 states(federal) with manual trans should work.
Mid-'80s Rangers with Fuel injection got the EEC-IV computer(OBD I), it was used in Rangers until 1994
In 1995 Rangers all got the EEC-V(OBD II) computers, these were used until end of production.
Ford doesn't publish software version cross references.
Part number for ALL PCMs is 12A650
Then there is a pre-number for year and vehicle model, and a post-number for software version
So if you have this: F17F-12A650-GA
F = 199, E =198
1 = 1 so F1 = 1991 model year, F2 would be 1992, F3 = 1993, E9 would be.............1989
7 = Ranger, Z here = mustang
F = Engine part
12A650 = Ford part number
GA = revision
There will also be a 3 or 4 digit number on the label in larger print, stamped on, that has the details of automatic, manual, EGR, CPS, and engine size, these are the numbers Ford should but never did publish.
Good read here on some EEC-IV numbers:
http://oldfuelinjection.packrad.net/page17.html
Actually a good site all around to bookmark