If I switch from TBI to Carb, will my O2 sensor matter. Do I have to change it if my 02 is bad. What are the effects if my 02 is bad on a car with a carb.

Thnks..

Assuming you go the typical non-CC carb route, the O2 sensor will become a plug in the hole in the header. No function anymore.

Thanks...

You can use is it to provide great tuning feedback through the use of a air / fuel ratio meter. I just did a similar swap and then installed an Auto Meter air / fuel ratio gauge. It has really helped me dial in the fuel curve on my new Holley 670. There is no more guess work. I can maximize power without wasting fuel by running to rich. The gauge is fairly cheap and easy to install.

A lot of people told me that a 670 would be too much carb for my 305 but with some fine tuning the thing runs awesome. No regrets whatsoever.

Thanks for the tips...

my car is non computer controlled, you mean I can just plug the a/f ration gauge scensor into my o2 scensor hole and that works great. If so, I will be picking one of these up soon.

You can use the existing oxygen sensor. Since you already have that the only cost is for the gauge and something to mount it in. I think the Auto Meter setup I bought cost me about $75. To me eliminating all of the guess work in tuning was well worth the investment.

I wouldn't say eliminates the guess work.
Reading the plugs are going to give you a look at how the combustion is going over a period of time.
While the O2 is going to tell you with some slop if you’re running lean or rich.

Mine was quick at detecting a lean spot off idle, so they do have there uses with tuning.

Would I say an O2 is worth it? It certainly was more appealing than some other options getting in to the 100's & even 1000's of dollars...

Ron