Help with upper engine noise

[ISHOU]

My 94 ATX with 170,000 just starting making a noise like this guy's SHO on youtube.

http://www.youtube.com/watch?v=cCdV-fqFpVE

Did the screwdriver to ear test and it sounds like it's coming from the exhaust chain area on the valve cover on front of engine.

Input appreciated.

 

[shotime1994]

Sounds like timing chain tensioner.