When I use dino,I always go with Valvoline VR1 20W50. I have a case of Pennzoil GT 25W50 I`ll use during the summer. When I go synth,I usually use RP. It`s a true grp IV (pao) synthetic which uses some grp V (ester) as well. Amsoil is a grp IV as well. Then there`s Redline with is an ester based grp V.