After I wrote my HEMI book, I broke a World main stud while assembling an aluminum motor. I used an iron World block in the book and had no issues so I talked to the powers to be and they said they did indeed have issues with their stud supplier. But that was over a year back, and they told me that new blocks would use ARP studs.

Then about 4 months back I had another aluminum World HEMI block delivered and it had all ARP.