MSD's engineering team has been working diligently the past year to improve our Multiple Spark Coils for the GM LS-engine platform. The coils fit in place of the OEM coils yet are capable of delivering higher spark energy to the plugs, topped with multiple sparks at idle rpm. Increased spark energy and voltage, along with multiple spark capabilities, help improve the combustion process of the fuel mixture to create an efficient burn. This results in improved throttle response, smooth idle and quick starts, plus increased high rpm performance! Do you have a built LS with bumped-up compression, a cam, or intake? How about Nitrous or Boost? Did you think about added spark energy to squeeze all the power out of your power adders? Can also be used as a replacement coil for 1999-2009 GM 4.8/5.3/6.0/8.1L and 2003-2007 Hummer 6.0L w/ VIN Z,N,T,V,U and B The 2-pin connector must be plugged into the coil. If not, the coil will not operate. This additional connector is for optional ignition/timing control. Connector and Plug Wire are on Opposite Ends.