I ran across a GM torque spec for an iron 6.0L engine main cap the other day that was different than the norm. GM specs the inner main cap bolt on this engine to an initial 24 ft-lb of torque, and then the bolt is tightened an additional 80 degrees. This technique is called torque angle and according to many fastener engineers, a more accurate way of tightening a specific fastener in a blind application where measuring bolt stretch is not possible. However, this is only good when all the conditions are new and exact bolts are used as with the main cap bolts on an LS engine where you use the factory bolts. A normal torque spec for a given bolt is based mainly on overcoming friction between the head of the bolt and the component (in this case a main cap) and also the friction between the bolt threads and the block. Only a small amount of the final torque figure is used to establish a specific amount of tension (or stretch) in the bolt. This is why the torque-angle method can be more accurate. Many enthusiasts incorrectly assume that a torque-angle method of tightening a bolt automatically means the fastener is a torque-to-yield bolt. This is not true. A torque-angle spec can be applied to any fastener, not just to torque-to-yield bolts. A torque-to-yield fastener is one that is designed to stretch a given amount and is intended to be used only once. A typical example would be factory LS-series head bolts that are torque-to-yield and should not be reused.