I've been using Rotella T diesel oil for several years now per recommendations on this board. I went to change the oil today and realized I was out. So down to the parts store and they were out, too. Then I remembered this post on Hemmings a few months back and decided to hold off til next weekend til I asked here.

http://blog.hemmings.com/index.php/2007/12/07/hmx-countdown-to-ignition-t-minus/

This bottle of Rotella T was rated CJ-4, which is the latest (as of 2007) specification for diesel oils and follows the spark engine oil trend of low zinc content. Only diesel oils rated CI-4 or earlier (CH-4, CG-4, etc.) have the proper zinc content. As for spark engine oils, look for an API rating of SE or earlier (SD, SC, etc.) for the proper zinc content. Don’t do what I did and buy diesel oil expecting it to have enough zinc for your engine break-in.

So have they changed the formula? Do I need zinc in my old 361? (which has never been rebuilt to my knowledge.) Any better oil out there than Rotella T? Thanks.