I have an 87 irocz tpi, i swapped the 305 for a 350 and put some headman street shorty headers on it. Everything is back together and runs good. One thing i forgot to do was weld in a bung for my o2 sensor. So i think i need the o2 sensor for the car to run properly. My question is, if i need the o2 sensor where should i put it? i think im gonna have to take the driverside header off to make it easier to weld in the bung. Any thoughts or suggestions?

 

in the collector but be sure you mark it up so where you install it you have clearance when the engine is installed

 

As close to where the stock one was on the original manifold. If you weld it in too far away down the exhaust,then you may need to buy a heated type o2 sensor or you will get a code 13. The stock type sensor may not get hot enough being that far away.