Hello, New to site but long time ford man. I have a 2001 F150 5.4 with a cold air kit, k&n, tb spacer, and headers. Well a few months ago I had a cracked upper intake. The one that was in my truck had what look like dual chambers on the plenum and the new one just had one chamber but little deeper. So thought just new style for aftermarket. Hate to say but have lost HP!! My guess is somewhere around 25-30 HP. So my question is has anybody ever had this or know why two different sizes? Upon some searching I did find the two for sale at parts stores but no one could tell me diff. between them. Any help is a plus!