Worn Cam???

[Thunder]

I recently pulled my oil pan to do my rear main and noticed some scoring and wear on the camshaft lobes. I'm wondering if this could be the cause of my engine inconsistency. It runs a little ragged but nothing terrible, at least I think so for something with 260k on it. Just wondering what the signs of a bad cam are, and how much of a PITA they are to change out and what cost?
Thanks

[jpthing]

From MGAguru.com:

A worn camshaft can also cause bad running. This causes different symptoms depending on how badly worn. With mild wear the cam lobe will have slightly reduced height, or a flat spot on top, sometimes refereed to as a "square cam". With correct valve lash adjustment the valve will open and close at the right time but will not open as far as prescribed. This will allow it to run quite well at idle speed up to mid range, but at higher speeds it will lose torque because the valve doesn't open far enough and restricts high speed flow. At higher speed it may lose so much torque as to seem to be misfiring. It may also cause a tapping noise at any speed, but most noticeable at low engine speed when you have less engine noise.

When a cam lobe is worn down a lot it may be refereed to as a "round cam". In this case the cam lobe is worn away so far that it comes close to being nearly a plain circle close to the base circle of the original cam. Here the valve may open late and close early, and may also have very little lift. With just a little lift it may run almost normally with just a slight shake at idle but will seem to be completely misfiring on that cylinder at any speed higher than slow idle.

To inspect for a worn camshaft, measure the valve travel at the top of the valve spring as the engine is turned slowly by hand. With the camshaft removed from the engine you can measure the cam lobes directly for base circle and cam apex height. Subtract base circle diameter from total lobe height to get cam lift. Multiply cam lift by the rocker arm ratio to get valve lift.