Jim, I thought there was an SS radiator as well. Is that the mid (early) year change 455/manual trans. with A/C or Stage 1 (i.e. w/o the trans cooler)? It should show up in an early assy. manual drawing. The two drawings I have are 2/3/70 (attached) and 4/24/70 & both charts are the same. From this chart, it appears that all GSX's, except in the case of a non-A/C Stage 1, got an upgraded radiator with the A/C cars getting the HD Cooling "SW" and the non-A/C standard 455 GSX's getting the same "SJ" that the GS 455 A/C (or all Stage 1?) cars got. Interestingly, Heavy-Duty Cooling (I7) was available on any A-Body and got an "SW" but was not an available option on a GSX so apparently there was no way to get the I7's H/D cooling "SW" radiator on a non-A/C GSX. Also interesting that while the chart does not specifically call out the Stage 1 option, Stage 1's did get an upgraded radiator. Did a non-GSX Stage 1 with A/C come with an "SJ" or did it get the upgraded "SW"? I know that the later non-A/C Stage 1's got the "SJ." I always thought A/C & Stage 1 cars got the full I7 HD Cooling package, but apparently in reality, they only got an upgraded radiator along with all of the other HD cooling components (Fan Clutch, 65A alternator, and fuel return line on 350's). Being that at least according to this chart, that is the case and if the "SS" is as described above, was there also an early '70 radiator for manual transmission cars (no cooler) with HD Cooling (or Manual/Stage 1 with A/C?) or did those get an "SW" (with the plugs left in) from the beginning of the model year? If so, that would be the rarest of the rare. Only an early original manual trans/I7 car or early drawing would be able to prove one way or the other. I know there are several threads on here about all this, so maybe this is all redundant - Maybe we need the definitive radiator thread as a sticky. It'd be interesting if anyone has any earlier drawing revisions.