http://1954advance-design.com/Web%20images/casting-code-photos/low-press-codes-ser-nums.html
Tom, I was already going to email this to you. I'm kinda tired tonight so I didn't try to look it up for you. You might be able to find here. Also, search the forum for the topic and you will probably find some other reference pages that allow you to decode engines by their block numbers. Talk to you soon, Don