Do an internet search for bolt torque values or fastener torque values. Each bolt manufacturer will have slightly different values, but the numbers are pretty close to each other. They will specify size, grade, thread count and things like dry, oiled, etc. When an OEM auto manufacturer doesn't specify a torque value, refer back to a bolt manufacturers torque value. For the studs, you would probably be safe to assume they are not grade 8's and could use the grade 5 torque numbers.
Google search for fastener torque value.
