From my research, they have been listed at pretty equal values lately.
Look at this car, it's one of two on car sales at the moment. This car isn't finished to a high level and they want $50k for it.
https://www.carsales.com.au/private/details/Datsun-260Z-1974/SSE-AD-5106445/?Cr=1
Those two 260Zs are priced right smack in in the middle point of the 240Zs for sale.
Boyblunda, did you cut and paste that spiel from somewhere? I'm pretty sure we are all up on the differences...