Slant Six Dual Exhaust

I saw a video posted under "why a six" that had a members 225 66 Valiant sounding awesome... I want my Dart to sound the same... anyone have specs on how to make a slant six a dual exhaust? Does it require a new exhaust manifold or can the split happen off the exhaust manifold...? Also, any recommendations on what Exhaust to run?
Any help would be appreciated...