Sorry Guys, my name is John.
Steve, I didn´t write there are unstamped cases, but only that many engines (by my opinion) are not originaly stamped from Honda factory production. I respect you as a CB750 expert, but lets look at the VINs:
1. E-1014143 does look like Honda font, but from detail it is not. Just compere it with French Sandcast E-1017118, these fonts are different in detail.
2. E-1017199 number 9 is not Honda font. Also the surface was just grinded by someone, so hardly could be original.
3. E-1014170 I know the engine numbers were not in perfect line, but this one is really stamped very badly. Please note, that Honda at
begining of 1970 was able to stamp the engine numbers nearly perfectly (not so chaotic like on first Sandcasts), so these VINs are strange for me.
4. 4 of 8 engines have not correct frame, or were replaced.
and for 5. Still nobody has theory for special clutch cover......... Why to make special clutch cover for few units of "french sandcasts"
It is everybody decision if to believe or not. But for me there is too much obscurity, my sorry to owners.