If you create a boot USB for booting into Parted Magic (free Linux distro) you can simply copy your C:\ partition directly to the HDD.
You'll also want to copy the System Partion into a separate partition on the HDD.
You can use the clone option or do this manually, but the MBR is actually part of the system partition so it should be fine.
Worst case scenario, you need to run a system repair at first boot which will recreate the MBR.
The other option is to do a fresh install on the HDD, and then use a Linux boot to overwrite the folders from the old windows install to the new install.
You'll need to backup the registry from the old install (boot to the SSD win8) then restore this registry in the new install.