This is beginning to become like the vàrious threads on slantsix.org. OHC head, it's been done, by a factory engineer years ago. It turned up in for sale section a few years ago. A better head, once again already done. Dutra did the blueprints years ago, nobody wants to fund the casting. Even the guy that owns a foundry doesn't want to take the risk. So you are beating a dead horse.
And there is no interchange between the flat head and the slant six so the "hemi" head won't bolt on, if it existed.
