oil type and oil pump

[fixkick]

really bob is right
the engineer is dead or retired, and now is well worn out. no?

here is your rod. clearance (note the 1 thou variance new and then the limit.)
min max limit
.0008 .0019 .0031"

so if you are at or beyond .003 limit, it might have issues. at 5000 rpm . (too old oil or too thing for any reasons)
main is 0.0023 max

what matters most is oil pressure at 5000 rpm this car run 3000 to 5000 ,

buy an oil pressure gage
run 5w-30 in it, the 30 number at 212F is what matters, (it should do well.) but how can i say that?, ive not miked your bearings.
but my pressure gauge never lies, and have my own custom low limit set to 10PSI, stock is 3psi, lamp on, (min)
this lube in dino form , failed in 1998. thus the warning. failed at the cam shaft.
my engine here, runs roller rockers to avoid all that.

look at dino oil
they take 5w oil (API rules) and add plastic VII to it , so at 212F acts like 30w.
Some oils dont go the distance here. (called shear rates)
Like folks driving 20k miles cuz mobil1 said to.