The " new" thing for header bolts is the adaptation of a wedge loc design.
This design of locking system has its place in the world.
My opinion is holding on headers when a gasket is involved is not the place.
When torqued the outer serrations bite and hold.
The inner ramped set seat down on each other.
The system works when vibration tries to rotate the fastener.
The climbing on the ramp increases the bolt tension stopping the rotation.
If anything in the combination gives like a setting gasket, the system does not work as intended
In Nords own words
Nord-Lock engineers highlight niche examples of when wedge-locking washers are not a suitable method to secure bolted joints.
While we are here , gaskets relaxing,
Sure , heat cycles excelarate the settling and subsequent loss of fastener tension.
But, try this
Put a set of heads and headers on with composite gaskets.
Don't preheat, don't start .
Come back in a couple days and retorque.
Oh, they'll move !!!
In my humble opinion ,about the time you are installing magical hardware you are "fixing" something else.
Like surfaces that are not true or over thick gaskets designed to " fix" a crappy header.
I remember being told the big crown in a name brand header was to better seal as the flange was bolted down.
Ah yeah, your header pulled during the final weld!!!
As others have stated is is hard to beat ARP fasteners in the longest length that fit without bottoming.
Nothing beats repeated retorques until the settling stops.
Good true surfaces , you dont need tricks and thick magical gaskets