62bigwindow. At first blush your statement is totally correct. -There is no serial number on the y-block Ford engines or transmissions that corresponds to the vehicle serial number that it came out of.
For the purist however, there are engine component casting numbers AND some components have casting dates that are 'correct' for the vehicle the engine or transmission came from. This also comes into play with transmissions.
I am not a numbers guy, but for someone putting together something like an E code or F code car, this information can affect the value of what they are restoring.
You are totally correct that the purists working on the restoration of something like a Corvette, this serial number stuff has got to be hard.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York