That U/C mark can also be used to set the cold clearance on six valves at a time during engine assembly. Adjust six valves (forgot which ones), turn the engine 360 degrees so the U/C mark aligns again, and set the other six. Some service manuals outline that procedure and indicate which valves to adjust. Recheck the hot clearance after a break-in run.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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