bearing shell codes

[Arfa]

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.

[Nurse Julie]

I don't think those markings relate to the colour of the shells. You would need to go by the crank and con rod markings to ascertain what was fitted from new but, they may have been changed in the past, so you can't go by the markings in that case. (not sure if your engine has been apart before). If in doubt, use plastiguage  to measure and determine what colour you require. Do they really need changing?

[Bryanj]

As Julie said markings on the back mean nothing at all, if you have jumbled up the shells from where they originally where you are stuck and will need to use the case and crank codes to order new and hope there is nothing worn, If you were incredibly lucky all the pin codes would be the same and all the sasing codes the same but never ever seen that happen

[Arfa]

Thanks, Interesting, all the shells are paired with where they come from so that's OK for now.

[Bryanj]

Then all you need is plastigauge and time