Did any of the cars in questions have numbers trans? Doubtful they would have stamped the trans and forgot the engine.

My car was a 407 SPD, not sure of the door sticker since it was stippered before I got it, the engine is a TA service block with I think a 4 26 70 date on it but for whatever reason I have no picture handy. Only is was put in when I built it in 13, in 72 it had a regular 340 short block installed under warranty, it had a 72 casting date on it. My trans is original and I am sure my original engine was stamped. So if you didn't know these facts then my car would support your theory, yet it has nothing to do with the assembly line.


I believe you have simply lucked up on 3 cars with service replacement blocks and yes, engines were cast in bulk and not every engine was cast every week.