That 10k figure includes ancillary items as well for building old iron where the hemi doesn't. I just built a 512 and it cost me just a bit over that out the door. That 15k Hemi still needs a harness, fuel system, computer, pan and exhaust. All that stuff being for late model is tons more expensive than it's old school equivalents as well.

Cost parity is coming, but I don't thinks it's there yet.