It's easier to simply grind a small groove inside the head bolt hole up to the oil hole with a burr, then you don't compromise the integrity of the stud as well. It literally takes 30 seconds to do.
The stud is not compromised . It is far beyond proven with all that were already done here. with very high compression race engines.
Also as stated some of the LA heads he installs are up to $4000.00 bare and he will not grind on customers high dollar parts. He supplies the fasteners and he has confidence in this modification from doing this on several engines at the other shop he worked at for 8 years and now in his own shop for over 7.
This is not a trial he is doing it with success for several years. I thought I would share the info. If you would rather grind the head being cast or aluminum with a grinder or any other method. Have at it.
If you look close at the stud you can see the weak area is at the base of the threads. years ago when Dave at HTA machine originally did this he checked on an old stud to see if it would torque as stated above . He went way over the recommended torque and the weak spot was the thread area.
