I don't know if NCRS (for Corvettes) has changed it ways, but a decade ago this was from their Judging manual.
"For instance, the following examples represent restorations and are not considered counterfeiting:
• Repainting an original black Corvette with black lacquer paint
• Installing accurately reproduced black vinyl seat covers in a car that left the factory with a standard black interior
• Stamping a 435-HP block to conform to the date/serial number of the original 435-HP Corvette in which it is to be
installed"
"For instance, the following would be examples of counterfeiting:
• Repainting an original blue car red and changing the trim tag to make red appear to be the original color
• Installing a red interior in a car that left the factory with a blue interior and changing the trim tag to make red
appear to be the original color interior
• Replacing the engine of an original small block Corvette with a big block and stamping numbers on it to make it
appear to be an original big block engine
• Replacing the carburetor on an engine with a fuel-injection unit and stamping the numbers and suffix code on the
block to make it appear to be an original fuel-injection car"
So if your "Born With" Engine was long gone, you got another date coded correct engine, and re-stamped it, you are fine. However if you replaced your 427/400 with a 427/435 and stamped as such, that was counterfeit. If it weren't for rules like this, there would be far less of a market for stamps etc.
