Just bought my wife a 78 camaro (I know, but it was a good deal and she was taking to much of a liking to my chevelle). This car has 61000 original mile, but had problems. The cam was shot, one lobe on number one cylinder was totally gone and there was an 1/8 inch or better concave in the lifter. What would cause just one lobe too wear so much more then any of the others? This is a totally stock SB.