Can a piston from a b block be used in a rb block? Considering if the piston are not connected to the rods, are they interchangeable if the pistons and bore size are the same ie 30 or 60 over. Does the skrits play a role in preventing say 60 over piston from a 383 to a 440 which is bored at 60 also? I know that the rod journals are the same but lenghts are different, mains are different also but I am not clear on the pistons issue thanks.

440 + .060 = 4.380 (4.320 stock)
383 + .060 = 4.310 (4.250 stock)
not even a consideration much more different than just the bore size pin heights are miles different!