It is easy to tell if a cam is worn out without removing the engine or the need for close inspection.
When the tappets become worn (normally 60,000 -80,000 miles) the tappet base becomes concave (dished), so that when the camshaft rotates through 360 degrees the tappet will only ride on the edges of the camshaft and only make contact in the centre when it goes over the (worn to shape) cam lobe. This has the effect of causing the camshaft to be brown in appearance and shiny on the edges.
The cam in a Rover V8 is hydraulic in design, which means when it is manufactured the lobe is cut at a slight angle so that it rotates the tappets, essential for them to fill with oil. Even when the lobes still look intact, if the cam is starting to discolour, it is well on the way out. It is important to change the cam before it starts to wear away quickly because the metal particles produced will rapidly cause further wear in the crank by becoming embedded in the white metal bearings and softer aluminum rockers and causing further metal particles to be produced. Replacing the camshaft and tappets before they get too bad will greatly extend engine performance and long life.
Longer engine life, increased engine efficiency, smooth idle and good power, cannot be expected from cams that look like this (and it is not an uncommon sight)
Although you can see this cam is showing all the discolorations mentioned, the Camshaft lobes showing are all becoming rounded on the shoulders, it's clearly been bad for quite some time, and will have caused considerable harm to the engine already, not to mention the engine's performance and efficiency.
It's clear to see that the tappet on the left is already showing signs or becoming worn, the centre is dished (concave). The trouble is that the cam and tappets will get a lot worse than this before you can actually hear them, and the gradual, long-term wear means you will not notice the power and economy losses either. So check the condition of your engine by the method we describe above, and judge for yourself if it's worth closer inspection.