Just my opinion, for what it's worth... (nothing!)
I would use the synthetic in a late model performance car (scat pack, hellcat) but I would use conventional in a classic, especially with a flat tappet camshaft.
I bought oil every time it was on sale.... till I put it all in one place, and realized how much I had. I use diesel oil in the diesels, conventional in the old cars, full synthetic In the new hotrod, and racing oil in the race cars.
