Can you use synthetic 10-30 in a 1968 vw beetle?

It is generally not recommended to use synthetic 10-30 oil in a 1968 VW Beetle. The original air-cooled VW Beetle engines were designed for use with mineral-based oils, such as SAE 30 or SAE 20W-50, which have a different viscosity and composition than synthetic oils.

Modern synthetic oils have different additives and can be too thin for the older engines, which can lead to oil leaks, decreased oil pressure, and potential damage to the engine components. Therefore, it's best to stick with the recommended oil specified in the owner's manual or consult with a knowledgeable mechanic who specializes in classic VW vehicles before using any synthetic oils.