Only if you want to use just 6 cylinders, and then your gas mileage will be poor...
Seriously, get the right computer for your 5.0 and quit trying to cheap it out. The computer has to match the number of cylinders and air metering scheme (mass air or speed density)
Copied from Steve89GT
There are a few different varieties of computers... just a few different calibrations.. Here's the #'s of most of the MAF computers that are around. A9L and A9P are the most common.
1988 MANUAL 8LD
1988 AUTO 8LF
1989 MANUAL A9L, A9S
1989 AUTO A9P, A9T
1990-92 MANUAL A9L
1990-92 AUTO A9P
1993 MANUAL A3M
1993 AUTO C3W
1993 COBRA X3Z
The harness itself is what is different.. Most of the computers are interchangeable, although I have never done it.
You can also use an auto computer in a manual... but not a manual comp in an auto..