Ticking Noise - 273

Rob,
The other issue we have to deal with today is the lack of zinc in oil(SM grade) causing cam lobes to wear excessively. The oil companies have been reducing the zinc content due to EPA concerns of plugging converters around the 100K mark and since the last flat tappet car built was over 20 years ago it's not a concern for newer vehicles.After you adjust the lifters and if the noise goes away only to return a few hundred miles later might indicate the cam lobes are wearing quickly. If you start getting what sounds like an exhaust leak under heavy acceleration then the cam is shot. I went through this with a BB Chevy last year, #6 lobe on the cam was worn so badly it looked like the fuel pump eccentric!