I agree-Ive heard a lot about hardened valve seats-but Ive never really had any problems with volvo engines and unleaded fuel. I also agree that its wise to keep them a bit on the loose side. I always feel comfortable if I can hear them-at least a little bit. Ive seen them tighten up a few times-not sure why, maybe on new valve jobs the seat breaks in or something. Ive even known folks to tighten their valves too much-drive a long ways-and do no harm.(one good freind had a valve job done-over tightened them and moved a couple thousand miles away. He called me telling me how bad his car was running-I never thought about a bad valve adjustment. A year later-and many thousand miles, he limped back on about 2.5 cylenders-we loosened the valves-and it was just fine) When cams go bad in B-20's, dont they go fast-and its very noticable? I would never worry about the cam in any B-20 unless there was an obvious problem-like the valves needing very frequent adjustment or something. Ive heard a lot about cams in early B-20 being bad-all the problems Ive had though have been with '74 volvos(this could be just a matter of bad luck though)