blazer project

...not change significantly with the No. 1 or No. 2 spark plug wire off, so it's not a connecting rod issue, and probably not cylinder slap.  If I listen at the valve covers I can hear the tappets, they're quiet.  This is definitely not a valve lifter issue, either.   The oil pressure sending unit seems to actually work, and oil pressure reads very high.  That might be a result of 10w40 in an engine...