Here is the breakdown for this.
C8AEH - C=Decade=1960's, 8=1968, AEH=A=Ford, E=Engine Engineering, H=?
As you can see C=the Decade, in this case, the 1960's. 8=the Year, 1968. A=Ford (Full Sized) (S would have indicated a Tbird from 1958 up...). E=Engine Engineering. H=? Normally, a Ford part number looks like this C8AE-6000-A. The 6000 tells you it is an Engine part, and the A tells you it is the first time the part was made. A B, C, D, etc, gives you the 2nd, or 3rd or 4th revision, etc... Here is a website that explains it.