For my new 1999 I sent in my oil during the first change over to M1 5-30. Here is the response from Blackstone:
So good news it appears. They only thing that is listed high is Boron which is has units of 145 where the expected average is 65. What does a high Boron count mean? %fuel was <.05 and 0 antifreeze and 0.0% water.
Overall, decent news.
SCOTT: Looks like this engine was treated to white glove care over its 77,404 mile life. As you can see from universal average wear, all these Toyota 4.7Ls look like that too. These engines are wonderfully wearing types and yours is not the exception. Universal averages show typical wear metals for an oil from this type of engine after about 5,795 miles run on the oil. So the answer to your question is, sure you can run the oil longer. Try 5,500 miles for the next sample and we will be able to tell you how you are doing. You may be able to run longer than that.
So good news it appears. They only thing that is listed high is Boron which is has units of 145 where the expected average is 65. What does a high Boron count mean? %fuel was <.05 and 0 antifreeze and 0.0% water.
Overall, decent news.