So in classic production, it seems clear that you need to have factory:
Frame
Engine including original displacement
Tank
Side covers
Wheels
Seat
Fenders
Exhaust
Swingarm
Drive type
Etc.
That make sense. But how about less obvious examples such as:
1-Must the original exhaust retain 100 original unmodified(gutted or partially) innards in the muffler section(s)?
2-is the addition of an oil cooler OK?
3-is any form of minor non speed or aero benefitting chassis bracing(minor gussets,etc) OK?
4-the ride height must remain 100% stock?
5-vintage (but higher quality) aftermarket rear shocks of the same length OK?
6-engine may have non OEM (yet factory bore) pistons, cam, cylinder head work correct?
7-would the engine specifically need to be from the same year of the bike of the same model? As in for the sohc CB750 which the model ran from 1969 through 1978(with ALL years being rules compliant), could someone install a 1978 sohc CB750 engine in a 1970 sohc CB750 chassis with ALL the rest on the bike being 1970 vintage? Same basic engine architecture, same bore/stroke, identical in outward appearance, same original power rating.
Thanks in advance.
George