Valvoline VR1 Racing SAE 20W-50 or 60W High Performance High Zinc Motor Oil 1 QT, Case of 6
It works this way: 20/50 pours like 20/30 or 20/40 on a cold day. At 100*C, 20/50 pours like 50 & 20/30 pours like 30.
I use 10w/60 in my engines & recommend it for engines I build. I live in a hot climate & this oil gives the best protection at both extremes. The same company [ Penrite ] makes a 30/70 oil for worn engines.