Has anyone every had an issue with the SuperSprint (what I have) or the OBX header make a loud metallic buzz around 4,500RPM?!

I have singled out a loud buzz at that RPM behind the cam cover. I have checked the heat shields, not that,

Maybe the ball and socket? Might need to see if the springs are loose and the engine vibes at that RPM are making them rattle.

 

make sure the header spring nuts are tight. If not that check motor mount bolts.

 

Well it wasn't either of those 2 items. Checked all the heat shields again as well and still nothing lose.

I cant image a leak at the flange would make a sound like this as I have dealt with many of those over the years.

 

i wouldnt doubt it. I'm getting a flex pipe welded in and taking the doughnut out. mini leaks like crazy, but by creating a vacuum and pulling in air from outside. Really hurts performance as it causes a good bit of turbulence in the exhaust, Plus the post cat 02 sensor is reading that im running lean and has richened up my car ALL the way ans still throws a lean code.... (im not running lean... my tail pipes put out soo much black carbon it aint even funny...)

 

Well it might be my timing chain lose. Picked up a new tension plunger so we will see if that is a fix when it arrives.