Never used CAI for Monte Carlo 3900 engine for sale.  This intake is made specifically for the 3.9L engine by Cold Air Inductions.
It uses the stock air intake tube, but comes with an insulated aluminum airbox with removable lid and a 9" filter.  Also included are a hose clamp for connection to the MAF and screws and clips for mounting the airbox to the fender.
Must sell due to unexpected expenses.  The manufacturer sells this unit for $265.99 + shipping; I'm asking $200 + shipping (a 25 % discount).   The photo below is how the intake looks when it's installed (photo from the company's website).