Is this a 3963512 casting?

[bergy]

Yeah - Fall of '68 through about March of '69 the date was cast on the lower side. It was moved to the upper flange because of the problems wth sand sticking to the pattern on the lower (drag) side. Pattern release spray would puddle on the date charactors on the drag and cause the sand to stick to the pattern. The upper flange location for the date tag was machined into the patterns, but not used until all of the patterns were converted. Thus, you will find the upper tag location with a "blank" tag in it (not ligible)on transition castings. The big blocks were all cast on line #1 and my recollection is that there were 4 sets of mold line patterns for 512 blocks.