351C 4bbl motor - seized

[Calicat]

This fits with what Hemikiller had posted:

Open chamber vs closed chamber

The “dot” was added to the 71 M-code’s D1AE-GA closed chamber 4V heads just after production started. I have seen several early June ‘70 cast examples sans “dot”, but everything after has it.

So now I am wondering if the dot cast on the heads really had anything to do with closed or open chambers at all?