I can hear the coolent boiling but the temp guage is at half? is the gauge busted???

 

The temp gauge is pretty much a dummy gauge unless you have a 1998 car. It reads a hair below 210 whether you are really at 200 or 220, or so it seems.

 

check your radiator cap. if it isn't holding the proper pressure the coolant will boil at a much lower temp.

simple $5 fix possibly. just make sure it's for the LS1...they have higher pressure ratings than most other cars i think

 

do I need to get the GM cap