I think Rotella is a good choice for any hard working engine.The additive package needed for a good diesel oil has good acid neutrilizers and most if not all styles still have zddp for protection of our cam lobes and followers this is denoted by NOT finding the words "energy conserving" on the round symbol where the service classification (se,sf,sg,Etc) is found.
Most modern automobile engines are built with tighter clearances than our stovebolts and need oil made from thinner basestock to allow proper flow especially during warmup.
In multi grade oils,(10-30,5-30,etc)the lower number is the basestock from which the grade is formulated by adding viscosity modifiers that delay thinning as oil temperature rises--so 10-30 and 10-40 would have the same cold flow ability(like sae 10) but the 10-40 would not thin out as much at 210 deg F which is where the upper rating is found.
Multi grade oil DOES NOT get thicker at higher temp, it gets thinner but does not get as thin as the straight grade at the same temp.
For some good oil info from questions answered take a look at
www.bobistheoilguy (not this Bob)
