Lucas oil stabalizer does thicken the oil, same thing happend to me, and anyone I know only uses 20w-50 in race applications or jet-boats.
Is the zinc additive only for break in? Seems odd to need a special additive to run a cam all the time...
My builder told me to use zinc additive all the time or cam go flat

. Well i called a diffrent parts store an they got the zinc additve i can add to my oil-i was thinking castrol 10w-30 with the zinc...Iv got so much oil pressure it leaks a little off the side of intake and seems to blow alittle out vavle cover.