I could possibly get shot down in flames for this, but this is what I’ve done and works for me. I’ve got the GGR stud kit fitted to my Escort Cossie, and the block thread was tapped straight to the bottom, as I believe the thread is slightly tapered inside the block. So when putting a stud in to the bottom of the thread will cause stress at the bottom. This is possibly what could cause the cracking. The studs were oiled and torqued to 15lbs and then I fitted a WRC four layer gasket and torqued the head according to the GGR instructions. I drive my car rather hard and is an every day driver (110 miles per day) and is going fine. (Done 20,000 miles now) Currently running 330 BHP on blues, set up on Power Engineering rolling road. As the gearbox is a bit dodgy, I’m running a lower boost, but should be 375 BHP.

Hope this helps.

Cheers
John