The OE B58 Fasteners are TTY (Torque to Yield), this method is cheap to produce in large quantity using mediocre material standards. This method of fastening allows each fastener to reach its maximum theoretical elongation to provide maximum clamping force given that material property and strength. 
The major problem with this method is that the fasteners are not reusable. The second problem is that under scrutiny of clamp load 2 fasteners side by side are not applying the same appropriate force within reason.  If we cannot rely on even distribution of load, we cannot rely on these fasteners and its showing in the failures we are seeing. The third problem is the availability of replacements, this means a lot of these fasteners are not being replaced during engine rebuilds.
The OE B58 Girdle fasteners may be fine for OE properties, but they are not adequate for increased output. On bigger power engines we are seeing fretting transfer on the main caps, between the caps and the girdle. Our upgraded hardware helps prevent this damage by preventing movement. These fasteners are a must for big power B58 cars.
Specifically designed to support the load and tensile requirements of increased output.
Required to reach ASTM conformance certification.  All Material must conform to AMS batch raw materials.
Thread engagement and shank is optimized for each given bolt in its specific location. 
Meet or exceed a minimum allowable tensile strength of 190kpsi.  
Custom age hardened 
Corrosion resistant, there is no coating or plate film to wear or degrade.
Reusable indefinitely unless over yielded past acceptable elongation.
This kit contains 20 bolts, use a dab of engine oil and toque to 30ft/lb