After witnessing endless debates on this topic, and reading a lot of tech stuff, the only reason for staying away from
synthetic in older tech engines is the leak issue. It seems hard to dispute the results of endless technical papers that show that the
synthetic stuff is far superior from a durability, and "slipperyness" standpoint. However, it seems to be the "slipperyness" that causes the leak issues in older technology engines.
However, I'm staying with Valvoline conventional 20/50, for the leak reason in an old FE. Most of us change our
oil maximum every 6 months, regardless of the mileage, or every 1-2K miles, and the coventional stuff doesn't have time to break down in that time.