[osrclint74]

Engine OIL...Just wondering what everybody prefers, how often do you change it, what temp you run your truck at, what engine, what climate???

I have a 84 square body, slightly built SB, 5 speed Muncie. I live in Upstate NY(between Buffalo and Niagara Falls) 90 degree summer months, driven into the 40 degree days in the fall. Thermostat is a 165, stock 6cyl radiator with twin 8" fans and a puller flex fan on the water pump. Rarely hits 210 but if it does I flick the switch and keep it cool.

I've been running Quaker State 10W-30 in everything I've owned for almost 30 years without complaints. Religious changing around 2500 miles, sometimes sooner. Haven't heard a rod knock since the early 80's.

 

[Rhotpursuit]

@oldeerslayer can advise on a fan controller so that you can ditch the switch. The thermostat is too low...you need a stock range to get it up to optimal operating temp.

 

[bk2life]

I have a 84 square body, slightly built SB,

nice, any pictures?

90 degree summer …40 degree days in the fall.

perfect for 10/30

Thermostat is a 165,

too cold, should be at least a 180. You need heat to burn off internal condensation.

10W-30

this should be great for you. But, it really depends on the oil tolerances of your engine. If your oil psi is fine, and no issues, rock on..

changing around 2500 miles, sometimes sooner.

really no need to do this, but if that’s what you like, you do you you. But I don’t change until double of your mileages.
i use 10/30 and 20/0 some straight 40 and one takes 5/30, just depends on which vehicle, which engine. To me, personally brand name is a choice, not a rule.