Well those are some nice heads. They were the first of the FE head castings. All of them have machined chambers and production only lasted the first 90 days. After this Ford revised the castings to eliminate the freeze plugs and enlarge to chambers so they would not have to be hand machined. This was a costly process. The E head is the earlier of the two. And from what I understand the size of the EDC number had to do with the size chambers. Some were 69cc and pretty sure the E heads were 74cc's. They have lowriser size ports and are well sought after heads. The C with the F inside is the Cleveland foundry logo. Let me know the date codes and I can tell you the year/month/date they were cast. Look for a number/letter/number(s) sequence on the head. That's the date code.

G.