IMHO, I can't imagine that the factory ram air effect is going to equate into more than the equivalent of a pound of boost, remember that the air coming through the scoops runs into an air filter upstream of the carb. This all goes out the window if the filter element is pulled and you're giving her over 100MPH. Where the ram air does help to generate a few extra HP is by drawing outside, hopefully cool, air that will be denser than the hot air under the hood. I wouldn't be worrying about the advance at this point cuss I doubt that the signal below the butterflies will be impacted unless of course you're running a racecar in which case the vacuum line is disconnected anyway.