I was wondering the same thing, a single digit number for date code year seams a bit confusing. I.E. 54 or 64
This is normally not an issue as most casting numbers don't last more than a few years and almost never over 10 years. But, due to the water pump height of this block vehicles needing this couldn't use a newer block. So they either cast a bunch of them in the late 50's and still had inventory to burn up or they continued casting them due to continued demand? Either way, it's still in the book as of 1969 and maybe beyond...that's my newest book...
Mike B
