I know this has probably been discussed before (I haven't managed to find it) but does anyone know how much extra torque can be applied to arp head studs on an A series engine. The ARP site says m10 studs should be torqued to 62 ft-lbs and the tech wiki says that the "13" head bolts should be torqued to 58 ft-lbs. It seems like a large expense for an increase of 10% in clamping force. Is this right or can the ARP studs be torqued up more than that? I imagine there's some kind of safety factor involved.

If that's correct it would seem like for a significant increase (50-100%) in clamping force you'd have to go to m11 studs. Anyone ever done this?