264, 272, 280 are all for reference. You don't always get exactly what your buying. You'd need to specify the make of cam to be more accurate.
You can find the same '272 profile' but different makes will give different characteristics.
Generally tho you can fit any make 264 on std springs/retainers. But fitting 272 or higher you need to fit uprated springs/retainers.
Kelfords
Hks
Gsc
Brian Crower