your O2 is most likely a 2 wire narrow band. It is not going to tell you exact AFR's under WOT or cruise. With out a heated, wide band sensor and a way to display it, you will not know what AFRs you are running and risk causing motor failure.
I have a AEM wideband. it works great and is really accurate.
Some people here use the LM1 and have great success with that.