Ok so after all the work ive been doing to my truck the compression is dropping out of a cylinder. I ordered a long block to replace my motor with instead of taking it apart and trying to fix it and i figure if i have it out ill put headers on it and im not sure what to do with the o2 sensor that is on the stock header. Any ideas/comments on a good header. trying to be around 200$

 

I would not put headers on it. If you insist, buy the shorties that already have the o2 sensor hole in them.

 

what is your reasoning for not putting headers on it?

 

They don't fit that good underneath, and if you have only one O2 sensor, it needs to go in the y-pipe where it can read both sides of the engine. If you end up running long tubes and putting the O2 sensor in the y-pipe on it, it will be too far away from the engine and won't heat up enough to read correctly.

I can't remember if the trucks have two O2 sensors, one for each bank, or just one in the y-pipe.

 

Most OBDI vehicles just have one sensor, located on one bank of a multi-bank type engine anyway. On my 1985 5.0 it has a single sensor at the rear of the passenger side manifold. It does at least see exhaust gasses from four cylinders, whereas with a similar location on a set of headers the sensor would only see exhaust gasses from an individual cylinder. I have see this arrangement, though I imagine it wouldn't work well in the grand scheme of things.

 

It does only have 1 sensor on the rear of the passanger side. So what would the difference be if on a set of long headers you drilled a hole at the end where the exhaust pipe would meet and installed the o2 sensor there. All exhaust gasses sill would pass through there. I dont know much about this thats why im asking.

 

The oxygen sensor requires it to be within a certain temperature range to work. Putting the sensor farther away from the engine may prevent it from getting hot enough to read correctly.