Compare the diameter of the stud verses the factory bolt. You'll see what I am talking about. Once the stud goes through the head it restricts oil flow a lot. $1800 for T&D rockers why starve them for oil. All SB we stud get the grove in the stud. You can physically see the flow difference before and after while at RPM's above idle. 8 yrs of 8500 rpms and has been up as high as 9300 on the recall. After tear down the motor showed no wear from lack of oil. I would say his mods work. He Just finished another one and this guy is hard on motors. we'll see how long it lasts.
