Engine Oil recommendation for a 1969 Ford 302 cu in.

[amber pumice]

Would anyone know the best oil to use in this engine? It's a 1969 Ford Fairlane with a 302 cu in V8. It seems that I should use 5W-30 or maybe 10W-40 but I'm confused by synthetic v semi synthetic v dinosaur (which I assume is not synthetic?). Then, what about zinc, do I need an oil with zinc or should I find a zinc additive? I'm looking at temperatures of 25F min and 55F max over the next 6 months, if that's relevant. It's garaged indoors and won't be driven much if at all this winter. This is what's available in my local car parts store: https://partsforcars.ie/catalogue/ofgrade-oil-by-grade Thanks.

[stark shard]

I honestly dont know much about those specific engines, but if i will say anything, when it comes to classic cars, its usually best to choose a thicker oil grade. I would probably go with the 10w40 if you dont plan on driving it in sub zero temperatures too often. It means it wont be as likely to burn oil over time. For the same reason, I wouldnt use full synthetic oil in an old engine like that since it is thinner and more likely to escape into the combustion chamber. Maybe check and see if other people use 10w40 in those engines, and if it works, it will probably ensure the best engine health.

[amber pumice]

Thanks so much @stark shard ! I really appreciate you taking the time to respond. I'll keep that in mind, I won't drive it when temperatures are below freezing but it will be exposed to a little below freezing while parked up over the winter.

[stark shard]

👍

[hushed igloo]

if the oil viscosity is rated at 10w40 for a synthetic oil, and 10w40 for a conventional oil, wouldn't they have very similar if not identical thickness?

[stark shard]

Really, the difference between synthetic and non synthetic comes down to their chemical properties. Looking into it more, synthetic is supposed to be better than traditional oils, but it really depends on personal preference and price.

[echo zenith]

you need zinc if you decide to run sythetic oil

[hushed igloo]

I've heard blends are a bad idea because of the different chemical characteristics of synthetic vs conventional oil because they burn and degrade at different rates

[stark shard]

eh, thats mostly a myth to be honest, although you shouldnt mix and match them too often, its not the end of the world if you do