I have the AEM. With the car tuned so it runs well the O2 sensor reads rich from idle to WOT (12 to 11). I have a MSD ignition and Edelbrock 1411 carb. Anybody else have readings that rich?
Several things affect what you'll need to run it at but the biggest thing I've noticed is if you have a big lumpy cam you'll have to run it pretty rich to get it to idle decent. I have a fairly mild cam in mine and run the idle as lean as I can to try and get some fuel mileage out of it. Around 13.8~14 to 1 in drive is where I run it. At WOT it runs best right about 12.5 to 1