they have completely different bore & stroke.... the C model has a much shorter stroke so it has a pretty wild power band... but theres only about 3-5hp between them stock, if that.
mounting would be fairly different too, as the C model uses the engine as a stressed member where the B model - and ZX7R's - do not.
its definately the B model engines that people put into old ZXR750's.... not sure if they go into ZX7R's easily, perhaps another forum or even google would be of more assistance