[Razorback1980]

It's actually quite noticeable even to the naked eye....the lobe will be more round than flat. As Nick already mentioned, when the hardened top surface wears, it starts to flatten very quickly. Compression checks will sometimes help spot the problem as the valve doesn't open all the way and if the problem is an intake, the compression will be lower. I've never been able to spot an exhaust problem with a compression check though. I'll check the shop manual, but I'm sure there are tolerances there that tell you condition of the cam. One thing I have spotted with an extremely worn cam is poor idleing and you can take the plug wire off while it's idleing and it won't make a big difference in the engine speed but it will be some...much less of a difference than the other cylinders in comparison...if that makes any sense.