You can theoretically make any engine a "hemi".... but why? Hemi's ****. The lack of a squish pad doesnt allow cooling, and thus burns hotter than traditional style valves..thus needing less timing, but more octane to attain the same power as tradional heads would.. A hemi head, theoretically, should never out-perform an identical setup on the same gas, due to the lack of cooling. However...for nitro and alcohol cars...hemi heads are the most desireable, because you need to get that mixture to burn, and you can add all the timing you need.
A squish pad (the part of the head that has no dish) is designed to have the mixture forced onto it, and acts as a kind of cooling "area" or whatever you'd like to call it. The old hemi's had 2 plugs per cylineder, and forced the mixtures towards each other in the center, thus burning very quickly (similar to vortech's quickburn heads) but also burned very hot, and required higher octane to achieve the same power(on gasoline).
Basically, hemi's aren't really all that great... they were different...and never made the claimed power... and so I guess that makes them good?...no
Just say what I just said to him in front of a crowd, and when he goes to say "well Ill just put racegas in it" you say "Regardless of race gas or not, a tradional OHV head will perform better".
Now, of course, this is all subject to an incredible amount of variables, but for the lack of caring, and his ignorance, he won't know any better.