You need to wrap your head around the idea that the industry drops off support in as little as 10 years, The computer is wrong, sometimes you need to go the aftermarkets website and look it up. At this point in time everyone needs to start using '95 when looking for parts. I would look for arms starting '81 up, they have not made 1/2-3/4 arms for years now. I got a set from the boneyard. If your willing to spend the coin you could buy aftermarket arms, I am running a set of CCP uppers on my '89 30. They are for C truck and fit just fine after I swapped the BJ. If you look on this site you will many examples of the 3/4 struggle with the lower arm and shaft. Many parts interchange. IE when I lost my upper hose about a month ago I had to start about '93 and I found Dayco 71884. On the websites it did not show for my '89 but for the 90's van. When I went to Dayco's site it showed it to be a trim to fit- fit most, everything from P G C and K truck from 81-95. The meat sack behind the computer ordered 3 hoses, because the computer is right. I asked for my part # and end of story. As you go deeper down the rabbit hole of GM truck front ends the most important thing to remember is your wheel bolt pattern and brake pad # and rotor thickness, then move on to Matching Ball joints. When it starts to paint a picture you can pull the trigger on you parts.