Tend to agree with AK. When you said shifting at 6800 and noise behind the timing cover I assumed you had the spring tensioner and it had failed. Since you've got the wedge- Keep Digging.

Any abnormal wear on the cam lobes?

 

will , I ll drop the oil pan tomorow and see what happens

 

no , all cam lubes look ok to me

 

Still on stock pistons?

 

You need to be looking at the piston to cylinder wall clearances if you don't have a broken ring land.

 

Ditto. You say the pistons were fine , but I'm betting when you pull them out of the cylinder one of the ringlands is broken. Ask me how I know

 

yes stock pistons .

ill pop piston #1 and see what in there

 

Hope you find the issue, curious to see what you find.

 

Didn't see if you said anything about checking the valve springs. I had a inner spring break on a dual spring and it also made a similar noise, and I didn't find it until after I pulled the heads --- what a waste that was.

 

so Im in the market for a 408 rotating assembly with 9.5:1CR any one have anny advice