[Formulajones]

I've used synthetics for decades in these old cars and don't have leak problems.

People don't realize synthetic oils have been around since the 1920's used in aviation. Amsoil was the first to bring it to the automobile market in the 1960's and in 1972 it was the first to be API certified. Mobile and Pennzoil came along shortly after.

In other words, synthetic oil has been around a looooong time.