Replacement parts on a 50 year old car don't change the underlying original pedigree of the car. (Who wants to drive with a 50 YO fan belt, radiator hose or tires?) Sheet metal on a 318 car is pretty much the same as a Hemi car.
A fender tag is one of the items used to document originality. Sheet metal doesn't.
So it's OK to transfer the drivetrain over to a 318 car and completely rebody an original high dollar pedigree car as long as you screw it's original fender tag back on?
