Revision 1 (most common on old Amiga accelerators): 64-66MHz is almost a given at 3.3v, had one or two do 70, and a few duds that weren't stable past 55MHz. No idea what the possibilities are with increased voltage.
Revision 6 (last one): Known to do 80-105MHz. (Had an Apollo that would boot at 100MHz, but without recognizing RAM.)
No experience here with the other masks. :-)
