OK, I missed the Cobra part of the question ! My bad .
All as mentioned above, plus, if it's a high end motor ($$$$$) send an
oil sample out for analysis. They will give you the amounts of different metals in the
oil and show if they are abnormally high. From this you can deduce what parts may be showing excessive wear.
I don't remember the Co.'s that do this, a google search should ferret them out.