I have a question regarding the 289 engine in a 63 Avanti. The engine sounded as though it had a noisy lifter so I removed the valve covers and proceeded to try and find it. The specs call for .025" hot clearance. When I checked the engine I found that the right hand bank ones were set at .012" to .014" and the left had side was at .016. I set them all to .016" as I felt if I set them any loser they would really make a noise. With the engine running now there is no definite one that is noisy they all clatter a bit. The fellow who owns the car says that it had run good at these settings. According to the speedometer there are 73000 miles on it. I do not have any history if any thing has been done to the engine. My concern is if the manufacture calls for the .025" setting they must really be noisy or is it that the lifters are loose in their bores. I am concerned that when the engine is running at its operating temperature the reduced clearances are going to cause premature valve problems. Any advice or input on this concern would be appreciated.