oil for 87 prostar

[Kevin 89MC]

Interesting read on the zinc, I may do more research when time allows. As far as oil, I've run Valvoline 10W-30 in mine for the 12 years I've owned it, based on the recommendation of the MC mechanic at the time. No oil related issues so far...
If you ask 100 people about oil recommendations, you'll probably get 90 different answers, and there's a very good chance that all 90 will work just fine.
Oil related engine failures (other than low level or pressure) are extremely rare, not sure I've heard of even one on this board ever.
Kevin