According to the factory parts manual, the 931 is for a non-A/C car. The 933 is the A/C version. Of course, either one could have had the core replaced at some point....either 2 row or 3 row. There are also at least a couple of other numbers that year that aren't in the factory parts manual, so, it's all a bit confusing. It think some of it had to do with what transmission it had to although they list some numbers that are supposed to be for either automatic or manual transmission. It's probably that the parts manual lists one number to replace either of the original assembly line pieces. I know there is also a factory original 930 tank, and also a 975 which I've had on 3 different Formula S's. The 975's I've had were all 3 row and with a shroud. I've had 933's with 3 row and a shroud too, so, who knows why they had two different numbers for basically the same radiator.
