I used one to tune a 225cid /6 with a holley 350cfm 2 barrel. I found I had to restrict the power valve channel restrictions to get acceptable performance from the power valve circuit. By cutting down on the fuel delivered from the PV I was able use the PV circuit (had to run a plug before) to lean down the mains and get a crisper throttle and better milage.
My 408 smallblock got an O2 kit last year when I moved close to work. I had been cruising I95 every day and the highway blasts kept it running clean. A little richness in traffic gave it decent manners. Once I moved near work I was constantly fouling plugs driving behind 90 year old grannies and suburban idiots doing 35 in a 40.
I switched to an HP holley main body and was able to tweak my air bleeds to get a better fuel curve for stop and go traffic without losing WOT performance.
No matter what you do the wideband will show you just how much of a compromise you have to make to get the car driving how you want. It still takes a real wizard to get everything perfect, but with a wideband and a vacuum gauge in the car you can tell which circuit is working in your carb and how close it is to where you want it.
