I've got my 400 in bits and am mulling over the usual growing list of jobs and parts. I can't see colour codes on either the main or big-end shells, but they are marked on the backing as follows:
Mains D6B-A-STD, big ends D56-A-ST, so are they A's or D's, or neither?
By the way I also have an attack of the broken piston rings, with number 1 cylinder particularly bad, but 2 and 3 both have broken top rings, seems a common problem from what I've read on here, including Julies terrific write-up.
Arfa.