8 3/4 Diff strengths?

As MrJLR noted. 3 cases with the 489 supposedly being the strongest.
Here is a link to a pretty good overview of everything 8 3/4. The same content seems to have made its way onto quite a few web pages now. None the less its a good resource.
Mopar Casting Numbers - MyMopar.com - Mopar Part Numners