I don't know what the specific difference is between 7447A and 7447B/C, but it's not the maximum rated core frequency as there have been 7447A chips rated at 1.7 GHz, like the MC7447AHX1700PC (see Freescale/NXP PDF linked there
Thanks, the NXP/Freescale qualification record is nice. And if you find somewhere also MPC 7447B or 7447C Hardware Specifications, it will be excellent.
Overclocking is now sucessfuly done, but at least I can store it for future cases.
BTW my 7447B is 1500 MHz marked version.
AmigaOS: Micro A1-C, AmigaOne XE, Pegasos II, Sam440ep, Sam440ep-flex, AmigaOneX1000
MorphOS: Efika 5200b, Pegasos I, Pegasos II, Powerbook G4, Mac Mini, iMac G5, Powermac G5 Quad