Hello. What type/grade of oil would you recommend running in a believed-to-be stock ’69 383? Motor is certainly beyond break-in, but actual miles are unknown. Car is street-driven (no track runs) in MN. Previous owner said he just ran whatever synthetic was on sale, which seems to have encouraged leaks. I have no problem spending a few bucks on oil, whether that be with conventional, synthetic blend, or other, although it appears full synthetic may not be the best? I prefer not to play with separate additives and intend to be consistent with whatever product I ultimately choose; had used 10w30 Z-Alt in a previously-owned car, but no longer being produced. Also, any specific oil filter pairings? I want very much to take good care of her and keep her in the family. Thank you again!
The factory recommendations are basically still appropriate.
In your climate, which has a huge variation between seasons, I’d use a multigrade such as 10W40. Synthetic is a good upgrade, primarily because oil pressure will come up faster when very cold. The prior owner’s advice about shopping by price is well taken. One of the versions labelled for “high mileage” engines, which have a bit more seal-swelling additive, can be helpful.
A cheapo Fram PH8 filter is all you need. Always pre-fill the filter.