Ok I have narrowed my choices for oil down even further. The Mobil Drive Clean Plus in 10w-40 or the QS 4x4 Blend in 10w-40. Both these oils are in the $2 a qt range and are available at the ol' Wallyworld here. I plan on about a 4k oci on a 3.0 Nissan (100k) and a 3.5 Isuzu (60k). The Nissan uses no oil and th Zu uses 3/4 - 1 qt per 3k (hoping to end some of this). I have heard/read that the Drive Clean lineup uses a Grp I base oil. Now is this so and is it bad if so? Is th QS blend a Grp III synth added to what Grp base? Which would be the better oil? Sorry for so many questions but this process is quite invigorating for me.