Help with letter in head casting number

[Dreaser]

Can anyone tell me if the letters after the numbers have any significance?
Thanks for any help!

 

[Xcudame]

I think it was a serialization of the different molds used to cast the head. In your example, mold "C" and "E(?)" were used. On blocks they used numbers like 2468130-6 for a 59-71 383. The "6" is the mold serial number. Realize they were casting hundreds of these every day for years. I think I remember Chrysler making over 3 million 383 blocks!

 

[Xcudame]

By the way, what we call "casting numbers" are actually engineering part numbers, but regardless it lets us identify parts. The main thing on a matching set heads is the casting dates are close to each other. Usually no more than a month (or two) apart.

 

[Dreaser]

I think it was a serialization of the different molds used to cast the head. In your example, mold "C" and "E(?)" were used. On blocks they used numbers like 2468130-6 for a 59-71 383. The "6" is the mold serial number. Realize they were casting hundreds of these every day for years. I think I remember Chrysler making over 3 million 383 blocks!

thank you so much!