For exotic niche market products like this, cost will always unfortunately be the downside. So naturally, with better designed port configurations may also come better and different intake port shapes and sizes that may no longer allow the existing intake manifolds or current headers to bolt on. So possibly new intakes and headers may be required because the ports are larger, or taller or spaced farther apart. Then comes the valvetrain, I would design it to use roller rockers and shafts already available for the SB or BB Chrysler engines as well as the valves, so those parts wont be custom or hard to find if someone wanted to build their head themselves.
