I should probably mention that my truck's 216 was rebuilt about 200-300 miles before it was parked in the early 80s.
It doesn't (and hasn't since I've had her) used any oil. I expect that to change after it loosens up a bit.
The Reason I went with Rotella-T was that I could find it with ZDDP at the time, and I went with a slightly thicker grade to see if I could prevent the drippy plug spots on my floor... That, and I figured that at 140° - 180°F, the oil would flow somewhere in the neighborhood of a SAE 20 or 30 straight weight.
The added bonus is that the tappets are a lot quieter.
Aside from that... Time will tell. [shrugs]
