The torque for bolts is set by the Type Thread Count and Size of the bolt and if there is any coating on the bolt threads. As an example a
3/4 in SAE2 with 10 threads per inch is torqued to 157 ft lbs if oiled it is 121 ft lbs, if coated with teflon it is 50% less than that..
Check the following website for guidelines. BOLTS AND TORQUE SPECS