Sometimes it takes a couple of valve adjustments for a new head job to stabilize. I've seen valve clearances go away pretty quickly and need a readjustment in the first couple of hundred miles. I guess it's caused by the valves and seats establishing their new running relationship. Hydraulic lifters pretty much eliminated that problem with their pretty liberal self-adjustment ability, but solids still need a followup adjustment some of the time.
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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