Not looking to get into a big debate but the hemi design was the greatest thing that happened to engine cylinder head development in centurys.That the demise of the hemi came at the hands of NHRA and NASCAR and no further development followed made the hemi design obsolete other than the feeble attempts of Ford and GM's alternate designs.With the advent of foriegn auto manufactures using the design in some semblance of the original configuration making some of their engine very efficient hopefully some sort of R&D will get the interest stimulated again.The biggest drawback(in my opinion) is the rocker and pushrod design and always felt that the attempts to eliminate the issues(like Ford) with the daul overhead cams that if R&D would have advanced the Hemi would reign supreme in racing venues today.The strides of manufactures to improve wedge and canted valve style heads has give them a slight edge over the obsolete under developed hemi heads as we know it.With the cost of such development and todays economy,I don't see anyone willing to spend the money for improving the hemi design for only a limited market.