Yes the system will always learn since weather conditions are always changing. If you drive the car in the morning when it is 50 degrees the learn will add fuel. In the afternoon when it is 90 degrees the learn will pull fuel out. So it will always be changing the tune although, it shouldn't change by much.
With a big cam you probably should turn off closed loop and learn at idle just to keep the computer from chasing its tail. If the tune everywhere else is good then you should turn down the learn limits so it doesn't hurt itself. For example, if you have learn turned on high and the O2 sensor goes bad the EFI system could dump a bunch of fuel into the engine by mistake. If you turn the learn limits way down then it can't do that.
