Losi 40Wt is 500 CTS or CPS. Also in Associated, its 37.5 WT. I believe Assoicated 55 WT is 725 CTS and 60WT is 800. Try this site, but also keep in mind that if you use one brand, stay with that brand to keep the viscosity of the oils consistent, as you will see they are all different.
http://www.twf8.ws/php/index.php?opt...per&Itemid=175