8BA Oil

[tubman]

On a fresh engine, I would use whatever 10/30 detergent that suits your fancy. Contrary to what others say, you don't need heavier weights or diesel oil. Stick with automotive oil and get the proper additive package for your engine. If it has been properly rebuilt, it should have the maximum pressure regulated to 55-57 psi by the relief spring in the oil pump. This is why you don't need 10/40, 20/50 etc. All they do is make the engine work harder and produce a little more heat.

Don't overthink this. Contemporary motor oil is head and shoulders above what was available when these cars were new and everything available is better than back then.

I will further editorialize and recommend running the stock bypass oil filter system unless you are planning on some serious racing or off-roading. The way the vast majority of these cars are used and maintained these days, the finer filtration provided is a real benefit. One last thing; if anyone recommends non-detergent oil, quit listening to anything they say.