the injector harnesses were all the same from 87-93..
its the computer and dash harnesses that changed thru the years(when i say computer harness,im referring to the harness with the 60pin connector for the EEC)
for example, an 87 injector harness will work fine with any year(87-93) computer harness..
but you cant use a 90-93 computer harness with an 87 dash harness...only an 87,88,or 89 computer harness will work with an 87,88,or 89 dash harness..
the oxygen sensor harnesses are also slightly different..the position of the looped wire is the difference..this looped wire is how i sent 12v into the SIGRTN and fried my computer..it was in the wrong position for my setup..
its very easy to avoid doing this(i figured this out after the fact,of course lol)..just check for voltage Key ON,then while cranking,clutch down in the #46 pin of the EEC connector with the EEC not installed..if there is voltage present,DO NOT install your computer..this means the jumper wire is looped in the wrong position,and you'll need to correct it first,or fry the EEC
that being said,you can use any year or trans o2 sensor harness,as long as you check first and re-pin the o2 harness connector if/as necessary
1987 Notch - N/A stock 302, TFS heads, Holley Systemax, FTI cam, Astro A5
Best so far: 10.92 @ 123mph with a 1.49 60ft