I have a 87 with a 302 and I am putting my own exhaust on, I have a bender and some pipe but as I was cutting the pipes before the first converter looking thing where there is still 2 pipes and I was gonna run it to the back like that but after I cut it I noticed a sensor of some sort after the converter thing where the pipe is just a singular one. What is this and how can I put it back in the exhaust after I put the duals in. I am doing a h pipe and thought that would be a good spot but idk how to do it or what it is. Thanks for the help in advance!

 

If it has a wire coming off it that plugs in to the wiring harness, that'll most likely be an O2 sensor - computer needs that to figure out the air fuel ratio. If that's what you're trying to replace you have to weld a piece in, probably into the h-pipe will work, that you can screw an O2 sensor into. You could try and cut the old one out and trim it up, or just go buy a new one.
If it's a piece of hollow tubing that goes up to the pipe that goes to the back of the heads, that would be for an air pump. That would be useless if you don't have cats. Probably want to block it off and disconnect the vacuum to the valve (or unplug the solenoid that feeds vacuum there).

 

This is what I did, worked out pretty well. I used a grinder to clean it up and flatten it out on the bottom side, since it was originally fitted to a small diameter pipe.

 

It has the tubing like you said. So it would be alright to just block it? And what else do you need to do? And will it affect anything?

 

There is all kinds of info on this. You need a different shorter belt or a dummy pully for the air pump to keep the same belt. Also need plugs to cap where the tubes go to the engine. I don't have it figured out but I've read up on it