That's an excellent idea. Back when Pro Stock was in its infancy, the AMC factory team couldn't compete with the available OEM heads, so they took four (4) heads and sliced them horizontally with the dividing line slightly more than 50-percent high on one set and slightly more than 50-percent low on the other set and welded the two bigger sets together, creating two heads with ports that were considerably taller then stock. It worked; they started winning races, but NHRA was under pressure and finally disallowed that procedure. Lotta work...
I think that could be done with a /6 head. Tall ports...