Early Double Digit Block vs Heads Date Question

[BGlover67]

This is a request for info from any early '67 owners.  I'm trying to understand engine casting dates relative to head casting dates on early 1967 GT350's.  I've spoken with a few owners so far and found some interesting results.  You can contact me privately, you don't need to post any dates on here if you don't wish to.

Thanks in advance.