Collector ? Flange ?

EA885B71-8B8D-406C-A02A-4252F54F0D4D.jpeg 5FC6F103-A9E0-4984-98E0-3D5A52FDBA51.jpeg ? I'm not sure what the piece is called but the part where the end of the headers reach that have the 3 holed collector that connects to the exhaust pipe that goes to the mufflers on down...

The headers I have don't have that part doors anyone have an idea how I worked connect these to the pipes have now ?
The mufflers I had one had this piece but the new headers I am installing, Hooker Super Competition adjustable headers (5303) don't have that part just a straight long collector ?
Any ideas ?
Thanks
Maps