For those of you who still have a restrictor ring in your Atomic 4 Stevedore models, I have some advice on removing the ring. I have tried to pry it out unsuccessfully a few times over the years. I have bent several screwdrivers and other tools trying to pry it out. I was finally successful. I cut the ring in 1 place with a piece of hacksaw blade in one of those cheap little blade holders. This ring is steel and took me about 15 minutes of muscle cramping sawing to get thru. I then found that I could pry the ring out with the long jaw side of an open end wrench (either a 9/16 or 5/8 fit well). The wrench gripped well and gave good leverage against the other side of the intake, and was very strong so it didn't bend like every other tool I'd tried in the past.