What O2 to take reading off of? Left, Right, or Rear?

 

Either one of the front O2 sensors will work.I have that guage and think it's pretty useless.

 

Why do you think its useless?

 

The O2 sensors constantly monitor airfuel mixtures and the guage sounds like a great idea.In reality you have a light show constantly changing from red to yellow to green around town and at full throttle it shows rich.At engine speeds that the mixture would be critical,the driver is to occupied to monitor the guage.I thimk a fuel pressure guage is more usefull.

 

I was thinking the same thing when I was dressing mine out with gauges. The fuel pressure will show you if you are running out of fuel, which helped me tremendously when I had a bad O-ring in the fuel regulator. As soon as it would go into PE mode, the pressure would drop. Parish said he used his in tuning his monster. He said it was enough to tell him that he needed to get a fuel pump ... good investment if you ask me!