All of the other bearings were destroyed? On the small block Chevy I am building, there are 3 main oil galleys. One for the left bank lifters, right bank lifters, and one for the cam and main bearings. There are plugs at the end of these galleys and if any plug were installed too deep, it could block off some of the drilled oil passages. If this were the case with the rear plugs, there would be no oil to either the cam bearings and mains, or one bank of lifters and the corresponding head. If the center front plug were in too deep, there would be no oil to the front cam bearing and front main bearing. The cam lobes are lubricated by splash from the crank and oil drain back from the lifter valley. If any of the lifter valley drain back holes were plugged, the cam would not get enough lubrication. This is also why Comp requires you run the engine between 2000 and 2500 rpm for the first 30 minutes operation, to ensure there is plenty of oil being pumped into the heads and draining back through the lifter valley as well as to ensure plenty of splash from the crank. Also, there was a link to an article posted earlier where the owner of an engine kept spinning bearings. He had a remote oil filter and installed the lines backwards so there wasn't adequate oil flow into the engine. Finally, Comp recommends you break in the cam without the inner valve springs installed.