I ran Torco Racing oil for 30 years
Various different viscosities, some with a synthetic base in all my race cars,
I never had any failure because of any issue with oil break down, loss of lubrication value
I had to change it more often when running Methanol, turned to mustard looking baby diaper chit
plenty of Phosphorus Zinc Oxide {or now ZDDP} additive blended into most of them too...
I agree for the most part, there's allot of mumbo jumbo agenda's
out there when it comes to oils & Zinc content, depends on who you ask,
ask 10 people seems you'll get 10 stories/likes or dislikes
I have {had} a buddy Doug that works for Chevron/Standard oil
My Grandad Whitey worked for Shell Oil as an Engineer for 40+ years
My Uncle Ron worked for Chevron/Standard Oil as an VP Engineer for 40+ years
My buddy Doug in the Richmond Ca. CRC {Chevron Research Center},
he did destructive tests on different oils all the time, many different brands &
different types of tests, fuel/chemical breakdowns or dilution, longevity, wear & cleanliness
he was also a devout Div. 7 drag racer, he also affirmed/confirmed my thoughts about
Torco Racing Oils
I use Royal Purple 10/40 full synthetic in my since new 99 Dakota SLT 4X4 5.2ltr/318 Magnum hyd. roller
with 1.7 ratio Harlen Sharp full roller trunnion pedestal type roller tip rockers, a few other bolt on stuff,
it has 56k now, no signs of any issues or undue wear, knock on wood...LOL
Change oil every 7000 miles or so & change the filter every 3500 miles or so,
supposedly I don't even need to change the oil even that often but it's cheap insurance anyway...
Have the oil tested a few times {by my buddy Doug @ CRC} & it's allegedly still good to go too...
Different strokes for different folks,
I stick with what I know has worked for me,
I'd suggest people don't get pulled into allot of the hype,
newest flavor of the month, when it comes to oils,
there allot of good oils out there, some better than others...
I know Quakerstate & Pennsoil have been like crap for me,
get dirty really fast, sludge really easily too {means it's breaking down}
& even tested like crap too...
Just my experiences, yours may vary,
it depends on driving styles, heat build up,
even the way engines are tuned, what fuel your using etc.
My step dad use to do a test tube test with oils, when he was still racing
he should me how different oils & different additive different types of viscosities,
thicken up or break down under heat, just a simple flame test,
it was amazing how quickly some oils boiled & turned to varnish/sludge...
Especially Pennsoil & Quakerstate...
he loved Valvoline & Havoline oils, I don't use either anymore...