Examine the bearing surfaces and the surfaces of the cam lobes for surface scratches; very shallow scratches can be removed with fine emery cloth or an oil stone, while any deep scoring will require a new camshaft. Mount the camshaft on V-blocks and use a dial gauge to measure lobe lift and run-out, rejecting any camshaft that does not meet the specified limits. Measure the journal diameters with a micrometer and reject any camshaft that does not meet the specified limits. If the bearings are worn, they can be extracted using a suitable tool, such as GM tool set No. J-6098, noting that it will be necessary to drive out the camshaft rear plug from the block. New bearings are installed with the same tool set, ensuring the cam bearing oil holes are aligned correctly: for a small V8, the No. 1 bearing hole should have oil holes equidistant from the 6 o'clock position, while the No. 2 through No. 4 bearing oil holes should be positioned at 5 o'clock, and the No. 5 bearing oil hole at the 12 o'clock position; for a Mark IV V8, the No. 1 through No. 4 oil holes must align with the oil holes in the cam bearing bore, and the No. 5 bearing bore should be at or near the 6 o'clock position. After installing new bearings, install a new camshaft rear plug flush 1/32 inch below and parallel to the rear surface of the block.