M103 Head Studs vs. head bolts

[Motor Head]

I have a 1990 300 SEL which recently blew the head gasket. I have had the head reworked through the Berg Works and I am ready to re-install.

I ahve read on this shop forum that head gasket failure on the M103 is inevitable which makes me wonder how well the stock fasteners maintain the clamping load necessary for proper operation or if there are inherent weaknesses in the head gasket design. Since I am considering the Mosselman twin turbo setup I'm worried that I will only make this situation worse.

I happen to live in the same town as ARP who are well known for their high strength fasterners. I brought them one of my head bolts and they came up with a 12 mm stud that will work on the M103 head.

I was recommended to me that, before I swtich fasteners, I look into the concept of angle torquing. I would appreciate as explanantion of why this is more effective than using a series of increasing torque adjustments using the settings on the torque wrench. Can you tell me what the ultimate torque spec is when you start at 55 Nm and then turn 90 degrees twice after that? My understanding is that head studs are much more forgiving on the block threads since the stud is fully engaged in the block before torque is applied. The stud I'm looking at has a 220,000 psi tensile strength and is commonly used in high perfromance applications.

Any input on this would be greatly appreciated. I tried attaching a picture of a mock-up using one of the head studs but the server says the file size is too big even though the picture is only 140K. I'll try to attach it to a seperate post.

Thanks,
Motorhead