Lots of British car guys use Valvoline VR1 in the Triumph/MG/etc inline 4/6 with flat tappets like the GM motors. 20/50 with lots of zinc. Also Brad Penn makes a nice product. But yeah Rotella is great and cheap. KTM factory race mechanics tend to run Rotella in their racer's 4stroke bikes because they believe it's better (and for sure cheaper) than the recommended Motul 4T. And those motors take a proper beating.
Last edited by Wiggles; 04/18/2022 12:26 AM.
