BlackStealth- If you cannot exchange the HC currently have, I would recommend that you buy the Black and Chrome Heater Core from BeCooling.
There are a few other HC models that are 6x6; I know that the Original ProCore was a modified Ford HC.
FYI, the CoolShroud does
not fit the ProCore Jr, it
does fit the ProCore(no longer in production).
Thanks to everyone for the complements, my goal as a fellow Moder /H2O cooler is to make quality and useful components for you.