I have a slightly annoying ticking noise coming from eather my driver side header or inside the valve cover. It is most noticable at a cold startup and when accelerating. It seems to go away at a constant speed. The engine and body have 18000 original miles. I Know the original owner, i have verified the original miles and I was givin the car through trade. It has always been taken care of regular oil changes etc. The stang had been sitting out in a field for 3 years due to rear end damage, and before that used only on occation. It runs very smooth and has great response, and drives great but the tick is kind of driving me nuts. It sounds nothing like rodbearings. Its not loud but kind of like a sewing machine. My best guess is a exhaust leak but it is so hard to tell. I just cant see there being anything wrong with the valvetrain but maybe lifters? I dont know. "I'm a rotary guy" I would welcome help seing I'm new to the piston world. Thanks a bunch!!!