They aren't using torque to yield because of the aluminum head as my old 6.2 diesel with cast block and heads have torque to yield head bolts.
They say torque to yield is suppose to hold better because instead of just torqueing it down were each bolt can have different clamp loads (say a bur in a thread that makes resistance go up so the wrench clicks sooner) with torque to yield that extra degree's are stretching the bolts to they have a more even clamping force. Now the reason people go to studs instead of bolts is because studs have more even clamping force.
To the op about this, measure your head bolts and call arp with the measurements and ask if they have anything else that would work. I just did this with my 6.2 diesel for main bearing studs. I got the thread size and pitch, depth in block before threads start and length of hole the stud has to go thru. Even tho they don't make a kit for my engine they still found studs from other things that will work.
Get your information from an engineering materials handbook instead off some idiot off the net.
RDS can be machined and formed to a stud or a bolt, take your choice, induction heated to around 2,200*F, then oil squenched for hardening. than had to slowly heated to around 1,300*F and cooled slowly or it will be too brittle and snap like a cracker.
In use, Young's modulus of elasticity is exceeded. for a torque to yield application that permanently deforms it. The spring type action, this is also how springs are made is what equalized the compression forces. And thus also a throwaway part. But still retains a degree of springiness.
Key reason for their use is that a cast aluminum head has seven times the coefficient of thermal expansion then on a cast iron engine block. They have to be able to expand, then contract to their original dimensions to maintain proper torque.
Another advantage of torque to yield, a smaller diameter bolt (or stud) can be used to make the stockholders happier.
Designing this stuff is a team effort, mechanical, materials, stress analysis, production, machinist type engineers. If you stay half awake during these meetings, can ever learn something, but also watch out for those bean counters, also always there with the prime consideration of cost. Then their is mostly the EPA and OSHA concerns for compliance.
