I originally was going to suggest a Cat dealer, but the JD maybe a good one too. You can ask ARP for the spec, I'm sure its with in the grade 8, I know that most CAT bolts are grade 8 plus.
Heres a nice bolt site

http://www.derose.net/steve/resources/engtables/bolts.html


Kicking self for selling off my Taskforce trucks.
Still looking for an LCF or conventional big bolt in decent shape.


As of 10-26-2022, A 55.2 Taskforce long bed now the work begins