Originally Posted By: JustN89
That V8 could run on baby oil. Go with whatever you would like.
That is almost true.
But the first question is, where is "TAS"?
Choosing a really perfectly suitable oil has a lot to do with climate, which is not PC to talk about any more. Automakers try to diminish that, and their liability, by spec'ing mediocre 5w-30 for everything. If you are asking this crowd, and really looking for an optimal answer, then any answer without factoring climate is not a complete answer.
I have run over the last two decades (and still), a lot of Toyota V6's and V8's, including that one in other platforms (100 Land Cruiser). A low-mileage LS430 is one of my next two used car purchases, especially since my area abounds in them. Flesh out your needs/driving/climate and your answers will be better.