I recently aquired a 1980 Porsche 924. It has nearly 60,000km (37,260Mi). It had been using 20w50 before, and I want to use a synthetic oil. Wondering which brand is best I browsed around on different oil company's sites, and noticed that most of the big brands don't sell a 20w50 synthetic oil. Valvoline was the only brand that had it. But after reading a few threads, Valvoline might not be a very good oil to use and that its not actually a real synthetic. Should I use the valvoline 20w50 (recommend weight) or should I switch the weight and use a better brand like mobil 1. Cost is a factor and I can't afford the most expensive specialty stuff out there, however it is a small one and I want to extend the life of this car for a VERY long time.