3927186 head dated late April 1970

[L16pilot]

Looking for a correctly dated replacement 186 head for my 70 Z28. Prior to me purchasing the car, the original owner scrapped one of the original heads during the engine rebuild because it was cracked and replaced it with an incorrectly dated unit. The surviving head is dated D280, so I would be interested in a single D270 to D30 head to keep it within the same week. Of course, another D280 would be ideal. Looking for a head that has not been ported or modified in any way. Does not have to be an original 2.02/1.60 head with screw in studs...just a nice original 186 core.