Mark,

It had responce that was faster than any engine I have ever ran. RPM was only a littl ehigher, but the header was way too short. I ran out of round tubing so I could not make it as long as it needed to be. I am going to remake it longer and cut to tune it. If I see a 300rpm gain I will be happy. That seems to be typical. But like I said, the responce was instant. Here is a pic of the header before the flange or round tube adapter is put on. It is 1" square 90deg angles I weld together.