Clearly my 455 auto A/C has a replacement radiator...no tag, no embossed ID that I can see with rad in place...no help there. Read every thread I could find and digested chart on assy manual page 11-4.3. SJ was go-to rad for my config until 10-26-70 page revision added the SS with a different part#. Since mine is an 05B build, I would have gotten the SS. Per thread research, both SJ and SS use IA and CF tanks, so my question is...what's different causing Buick to add another rad with different part#/code? Only thing left is core. Anyone know what Harrison was doing then with core technology that would've replaced the SJ...?