My '78 SC seems to be noisier than I remember after I got it back from a full top-end rebuild. I've only got around 1K miles on the engine, with a tune-up after 500 miles, and there is one valve on the passenger side that is so noisy I'm tempted to pop the valve covers and check the adjustments. Overall the valves are noisy but reasonable I think.
What worries me is the unevenness of the valve noise. Of course, if they were all as noisy as that one, I'd probably be freaking out...
Dan