There were various different radiators offered based on numerous other options, but I'm not sure what all GM used to base these on.
Just took apart a manual trans '85 K5, 305, that had a 3 blade fan, no AC, and a 2 core radiator that was not the same height as the core support.
You can speculate as to size, but if you are buying site unseen, you'll need the exterior measurements to compare. Bracketry and fan shrouds are different depending on radiator size.