So, you have just purchased a beautiful new set of coated headers and you are installing a fuel injection system that requires an 02 (oxygen) sensor and the headers have no sensor bung... what do you do? You certainly don't want to drill and weld on those nice new coated headers, but a weld-in bung is a must to run the injector. In this case, a great location tor the 02 bung is in the collector (street reducer). Most header companies only coat the headers and not the collector.sThis works out great as the bung can be installed in the collector and than the collector can be painted with header paint or then sent out to be coated to match the headers.
The collector (street reducer) bolts directly to the flange on all headers. This is a perfect place to install the 02 sensor.
Make sure to locate the bung on the collector for the 02 sensor so that when the collector and sensor are installed the sensor will not make contact with the frame, crossmembers, firewall or floor.
Drill a hole in the co llector using a 7/8" hole saw. Now weld the bung into place. Do not install the 02 sensor in the header until the bung has completely cooled off.
With the 02 sender installed in the collector, you don't have to ruin the coating on the headers and it is placed in direct line with the jet stream of the exhaust, where it belongs!