Dont know if anyones had this problem before but, I had a lifter noise around the 5 to 6 cyl area, anyways I had the lifters replaced and the noise STILL persisted, some said it might be a leak in the exhaust, but, after listening to where the sound came from, and the loudest point was from the side of the head, next to the s/plugs, so, Dyna-mite took off the head, and found, the valve guides had come loose, it explained the loss of power also, (very noticeable too), it was a FULLY reco Streetfighter head, admittedly 2 yrs old, anyways, so next time YOU get a noise that sounds like lifters, check to where the noise is coming from first, before you start spending money....