This subject comes up several times a year and everyone has their opinions on what to buy. However, before you spend your hard earned money on "boutique" brands, I suggest you read
THIS. The author is Duke Williams and he's probably
THE go-to guy when it comes to oil. Do a Google search on him and you'll find a lot of information.
Also, as an update to that article, Duke posts a lot on the NCRS website and here's something he posted last year:
I was at Walmart last week and noticed that some brands have the new CK-4 primary service category and some are still CJ-4. The API and manufacturers state that CK-4 is "fully backwards compatible with prior C-categories." There is also a new FA-4 spec that I will get to shortly. I know many of you are hung up on brand names, but don't just blindly pull something off the shelf because it looks familiar. Verify the the "API donut" on the back carries a primary C-category, which will likely be CK-4 or CJ-4. The FA-4 is for new HD engines that should hit the road this year. They will be available only in xW-30 grades and the emphasis is on lower internal friction for better fuel ecomomy and less CO2. There will also likely be a reduction in "heavy metal" additives, which means less ZDDP. Other anti-wear additive will take their place, but I don't know if they are as effective. New HD engines will have detail internal design changes like bearings and rings to be compatible with FA-4. I have not yet found any detailed FA-4 specs from any manufacturer, so I don't know if they will be suitable for vintage engines with sliding surface valve trains or not, so stick with CK-4 or CJ-4. Next time I buy oil I'll buy the least expensive C-category oil I can find, as I usually do, regardless of whether it's CK-4 or CJ-4. Just make sure you don't buy FA-4 for now.
In regards to the CK-4 or CJ-4, the best deal around is still the Walmart house brand Super-Tech CJ-4. At less than $10 bucks a gallon it meets
ALL the requirements of our older engines.
Ed