OEM
Steve will confirm, but my information is that your best bet is to go with the OEM Fiat Rod Bolts.
You can get get get an ARP main stud kit that fits: PN #203-5403
and ARP Flywheel bolts: PN # 209-2801
If you go for the ARP main stud kit and fly wheel bolts be careful who you order from. My order placed with an on-line re-seller in the US, was ordered and paid for at the beginning of February, and I only received the parts last week....so they have delayed my build by 3 months :sigh: