I picked up a set of these heads pretty cheap and was just wondering if they are worth the time to put them on. I already have the explorer intake and 70 mm tb and egr spacer. I have heard that the bbk headers can be used when putting these heads on. Those i have and know that at least number seven will be hard. Looking for some more opinions. What type of horsepower gains can I expect to see from them if any. Any input apreciated. thanks