hello everyone. I have a 79 seville. the problem is that I dont know if the 350 oldsmobile engine came with a smog pump or not. there are no exhaust rails, nor is there any place for me to install check valves. Also, I have a "yellow emissions flag" showing on my dash. I'm thinking that i need another o2 sensor. However, I'm not sure where the o2 sensor goes, but i do see a wire going to some sensor on the side of the exhaust tube. it looks like i have to take the valve cover off to get to it. sorry my post is so long. thanks in advance.