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Checking the lifters is relatively simple. Remove them (one at a time) polish with a soft, clean cloth and look at the end that bears on the cam. If it is smooth and shiny with a flat or convex surface you should be OK. Any chips missing at the periphery, cupped (concave) appearance, or signs of galling on the sides (where it runs in the block) mean that a new cam and lifters should be put on the shopping list for the next time you have the inclination to open the motor. Black "carbon specks" seem to come with the territory and, although not desireable, do not appear to be a death knell all by themselves. A "tree-ring" appearance on the face of the (usually cupped by then) lifter is a very bad sign.
Generally the lifters wear out first but you could attempt to shine a flashlight onto the lobes of the cam to look at them. Again, lots of wear is not good, chips, flakes or black spots are also not good. You should be able to easily discern the wear on the cam by the pattern of shiny rubbing marks that broaden across the lobe as the nose of the lobe is approached. If the shiny wear is just at the lobe (all the way across) you are in pretty good shape. If the wear is all the way across the lobe and extends down both ramps (oh, 1/2-inch total from start of wear to end) the cam is pretty worn and likely close to shot.
The best way to check the cam is to combine lift measurement, either by removing it and using a micrometer or re-assembling the engine and using a dial indicator, with the observations. If your cam lift is close to the specified value then the wear is within reason. Opinions vary on how much wear you can tolerate but to me, more than 0.02" of lost lift is severe and full failure of the cam is not far off.
Mike!
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