Thanks. They are on ebay. Here is one I just found.
[ame="http://www.ebay.com/itm/70-76-Mopar-A-Body-Black-Dash-Carrier-Panel-Cut-Out-for-Aftermarket-Gauges-/350837764857?pt=Vintage_Car_Truck_Parts_Accessories&fits=Make%3ADodge%7CModel%3ADart&hash=item51af8f72f9&vxp=mtr"]70 76 Mopar A Body Black Dash Carrier Panel Cut Out for Aftermarket Gauges | eBay[/ame]