BBC casting #1X157129AC still a mystery.

[Chris Cogan]

Bowtie Froggie is correct. These heads are from Central Foundry Defiance. The wagon wheel was the old logo. All Central Foundry Sites became part of GM Powertrain in the early 90's, so I would guess that these heads are service replacement heads from 1988. The date code uses a letter for the month (we didn't use I so it wouldn't be confused with a 1), then 3 numbers. First 2 numbers were the day and the last # was the last number of the year. maybe 058, 158, 258, who knows. looks like the pattern had a "sticker" and the numbers didn't get imprinted in the mold. Defiance finished production of the Mark late last year. (8.1 liter block, head and crank) The end of an era for sure. I will try to find out more about the casting #. Take care guys.