We replace a heater core that was leaking into the passenger floorboard on a 2003 Impala 3.4L engine, with a bench seat. To take the dash out here is a link showing that
   • How to Remove Chevy Impala Dash (2000...  

It took about 3-4 hours with two of us working, and filming started after we got it out, I just wanted to contribute since we had to figure out some things on our own. I hope this helps some people. It's doable with patience and after getting those darn clamps off the front of the heater hoses!