[madmaxx]

Check to make sure your emergency brake cable is not passing through your rear coil over spring. Check the driver side first. If you find it, tie wrap it out of the way.

Funny thing is the first cobra and SPF I ever rode/drove in was back in 2001 outside New Orleans. There used to be a SPF dealer there. The guy takes me for a ride and had a noise that you describe, his solution was to beat the living sheet out of the car, the noise was still there we did not seam to care, I was scared sheetless and he was having a blast. When we got back to the SPF shop he put it up on the rack and that is what was found.