I have the AutoMeter Wideband...it has data logging but I have nothing to hook it up to. Maybe there is an adapter. Anyways, you need the wideband. Mine reads AFR in Hg and also Lambda. I stick with the Hg. It has been a life saver. Dialing in a single carb is one thing, I have two edelbrocks in line. I have it tuned exactly where I want it to be.

As a plus, you can rent it out for $25/day to your friends and make some of the money back