i ordered aan aftermarket header and it has 3 open bungs. i need s13 o2 sensor for the top bung and i need something to fill the other 2. or anybody know where i can buy plugs. i went to advanced, home depot, and ace hardware already, but i cant find a plug that big in such a fine thread. plus its metric so that makes it a little harder......lmmk what you have or what i can do

 

Weld a nickel or somthing that size to block two of them, and then the one that makes sense to have the O2 sensor go to ,where stock placement is, weld a stock bung in there. You can put a wrench or socket on an s14 or s13 stock exhaust mani O2 bung and simply unscrew it, once you have it out drill out the bung in your new header to fit the stock bung,weld it in place and voila

 

i am an idiot and threw away my stock mani when it broke. my 02 sensor was in there lol i need a o2 sensor and im gonna weld the other 2 tonight unless i can find plugs (my welder works till 11 lol)