The most important part of torquing any bolt is getting the threads clean and properly lubricared. A dirty or dry thread uses up a lot of the torque overcoming thread friction, so I like to chase the thread in the block with a slightly dull tap to avoid oversizing the thread, followed by a good blast of compressed air, and cleaning the head bolts with a wire brush on my bench grinder. Lube the thread with a few drops of motor oil or 90 weight gear lube, and include a little oil on the surface where the bolt head meets the cylinder head. Be careful not to fill a blind bolt hole with oil, or you'll create a hydraulic lock that keeps the bolt from tightening properly.
I like to tighten head bolts in three steps, for instance, one torque sequence at about 40 or 50 ft/lb, followed by 75 or so, then the full torque of 90 to 100 for stovebolt head bolts. If you use a durable thread lube like Never-Seez, reduce the torque specification by 5 to 10 percent to avoid over-stretching the bolts.
Jerry
