That's a pretty common part number, so there would have been lots of cast dates. All small block heads were cast 4 in a mold on Spomatic molding lines at both Saginaw gray iron and Tonawanda foundry. Big block heads were cast 2 in a mold at Tonawanda. Each plant had one line pretty much dedicated to small block heads, although the pattern equipment could have been switched to another line if the need arose. The lines ran at 240 molds per hour at 100% uptime (generally - 80 % uptime was achieved in production). The lines ran on a 2 shift basis, with shifts extended on overtime as demand dictated. To my knowledge, only Central Foundry Division ran on 3 shifts (5 on - one off schedule on each molding line). So, as far as the production of any part per shift goes, you can do the math. We were pouring 2,500 tons of iron per day at Tonawanda back then & more at Saginaw gray iron. Fun times!