A good read on oil
Is 10/40 Castrol still a good choice now? If so will it have decent zinc for flat cam in a 360 mopar?
Short answer: maybe. Even though SN rated oils heavier than 10W-40
may have levels of ZDDP higher than 800 ppm, most do not. Many oils are out there that will fit your needs, but only a few are reasonably priced and readily available. Rotella T6 5W-40 is a full synthetic made primarily for diesel engines, but has the good old school anti wear package. Virtually all diesel oils will work fine, but this one works very well, and is cheap at Walmart. Quaker State High Mileage synthetic blend in 10W-40
only still has the higher amounts of ZDDP. Also cheap in 5 quart jugs at Walmart. Valvoline VR1 is basically their conventional oil with a bunch extra ZDDP added in. Availability is good, if not Walmart, then NAPA or other parts stores. All of these are available on Amazon.
There are many more that will fit your criteria. But they are harder to find, or more expensive, often both. Lucas, Driven, PennGrade, Amsoil, Redline, Royal Purple and more I'm sure.
