the local place says they dont know how to install a o sensors since there wasnt one on the original pipe. POS place. Can I just tap directly into the down pipe and screw the O sensor in? Do I have to have a bung welded on?

Nick

 

Nick get a spark plug anti fouler at autozone. then cut the end off and weld it to the downpipe. they make perfect o2 bungs and cost about $4. Tapping the pipe will probably just break.

 

todd thats a good idea!

or goto napa and ask for a nut with the thread pattern O2 Sensor bung thread M18 x 1.50.. and weld it on