Head part numbers

Can anyone help me with the part number on the heads? The engine is a 731/2 T but with a later 1974 CIS (with injectors in the manifolds not the heads.) The head part numbers are 46181K, 1-72. 4K18164. I am assuming the heads are dated 1-72 but everything else I'm at a losss. Thanks in advance,
Chriistian

Anyone? As my daughters would say "pretty please?"

Not mine, I believe I found this here or on Pelican, but might help you figure things out.

I also searched Pelican but found nothing. That's a huge help, thanks George! I really appreciate it. Christian