[jeffschevelle]

I have no idea about the original question and no dog in the fight. But it is very obvious to me that pictures of casting differences between a 1973 and a 1969 block don't have one single thing to do with what the metal content of either of those blocks is or is not. For example, 1965-66 396 blocks (both 961 and 962) carry the same casting numbers and part numbers across both years, but there are numerous significant casting differences between early 65 396 blocks and 66 396 blocks. That does not mean the metal content was any different. Maybe after 4 years the content was different, maybe it wasn't. But casting differences have nothing to do with that question.

And if I was going to weigh evidence and render a judgment (continuing the courtroom theme started earlier), I would find it very easy to believe the guy who is "a metallurgist and was superintendent of the melt department at the Tonawanda metal casting plant." Is anyone else posting in this thread a metallurgist? Is anyone else posting in this thread a former SUPERINTENDENT of the melt department at the Tonawanda metal casting plant (not just a low level laborer, but a SUPERINTENDENT)?

This is not the same as the silliness of an assembly line worker claiming he remembers what head marking was on a screw he installed on a certain Wednesday in between punching the clock to get his paycheck 50+ years ago. I find it hard to conceive of anyone who would be any more likely to know what the metal content of a casting was than the person who was "a metallurgist and superintendent of the melt department at the metal casting plant" at the time in question.

So what am I missing here ??