The VIN and casting date is located on the passenger side (right side as seated in the driver's seat). Those will tell the tale. Check out Krazy Kuda's How to ID a small block in the "How to Articles".
I was just reading that thread, and actually still ha e it open in another browser.
I cannot find the VIN pad right now and need a shower so... That's a project for tomorrow, I'm going to try and clean the block as I'm putting parts on it. I may also buy new spark plug wires