I don’t think the factory used anything special for bolts in that application.

In the MP engine manual, the specified TQ for the damper bolt is 135lbs.

The standard torque for lubed threads on a grade 2 fine thread 3/4-16 bolt is 144lbs.

The standard torque for grade 5 and 8 bolts are way higher.

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads