1970 3963512 Block Strange One

[3macs1]

Interesting Steve. I can see my friend in the engine shop possibly running into this since who knows who could have fitted the 4 bolt caps by the time he got the engine. It may not have been GM , but he was so specific and hit the years in question right on. At the same time I am not disputing the knowledge of the NCRS.
One thing that sticks in my mind is the fact these engines came out of cars that were put together in Canada. Would they do any engine machining I wonder. In the meantime I am watching the 512's.
Thanks for doing the research
Joe