theres something in Valvoline oil that causes some people to get a rash. i was using valvoline at one stage & whilst retorquing the heads & refitting the rocker gear my buddy that was helping came out with a red rash on his hands & wrists. we changed to penzoil & all was ok but i later refilled with Valvoline & my buddy's rash came back & he refused to work on my motor. Valvoline oil is fine as far as i'm concerned just we use penzoil for the sake of my crew member.