I think an S car is a C 2 32"2" the performance pack is C 5 32"5" (I get those backward sometimes myself CRS) This is purely speculation on my part as far as the order codes. It would really make sense if they were using 32 for 273 4 bbl but that didn't happen until 1966...1965 would still be 31 (under the A and B). I bet someone on here actually knows about the order codes but It's not me. I've never seen that before thanks for posting that.