oil type and oil pump

[fixkick]

always do what bob says. (but your oil gauge will prove him right or wrong, sure will. if pressure falls on a very hot day, watch out, I use gauges on old engines.
after all who knows the wear inside. not bob. not me. (you alone and your added gauge)

keep mind, a 1980 or 90s engine is not like a 2016 engine. and is vastly more worn.. (the clearances add up too, due to there run parallel.)
IN the summer, i'd be wondering how good my pressure is , at idle.. and if low who well it gets to the cam , through that tiny 0.050" head orifice.
the cam needs pressure and good flow....

i think the new coolants now mix, with the old dexcool it turns to Jello.
getting the green out of rear water jackets can take an hr of flushing (the laws of diminishing returns) ive cust it too, many times.
there is a block drain, but getting it out, oh boy, near impossible.

grade:
when the temperatures are mild they all work,see. ?
The manual is clear, what to run, why buck the engineers book, ? (he well knew all grades made, sure did) but climate matters, What to do in Norway, well , read the guide.
but a nice gauge will let you know what's up, at 120f in the shade.