What later recordings are there that might show this "reworked" voice? Can you recommend one?

I inherited the words to a lot of songs but I'm not a singer, not familiar with the mechanics of the voice--what is a "weak chest register?" Is this an anatomical flaw, or a psychological impediment? Is it a result of childhood illness, perhaps pleurisy as a child (that's being a bit sarcastic, but who knows?) or insufficient lung capacity? He did smoke, didn't he? It was a shock to learn that.

SRS