I was just looking at Jerry's website. He has some facts on an original unmolested 1967 z28. The engine data is as follows:
3914678 CASTING DATE J97, ASSM DATE V1121MO. The flywheel data is as follows: 3791021, DATED K157.
If I read this correctly the flywheel was cast a little over a month before the engine date stamp on the engine pad.
So, could some flywheels be original to the car but yet be cast up to a month earlier than the engine stamping date.
Maybe it was different in 1967.
what do you think?