I really don't care about the specs. I do know that I get the results I want with the materials I have been using. When the bolts resist being removed after being in place a year or so, the results speak for themselves.

For years I used regular Loctite red on glo engine muffler retaining bolts with the same results. I still use that material on my helis as the high temp loctite seems too strong for the purpose and I fear the smaller bolts might twist off when attempting to remove them.

One thing that I rarely hear mentioned and that I do on a regular basis ..... I use muffler retaining bolts that engage as many threads in the cylinders as possible. Sometimes these may be up to a 1/4" or so longer than those supplied with the muffler / engine. I feel this gives much better support for the muffler. Some bolts as supplied may only engage 3 or 4 threads which is simply not enough to retain the muffler properly. Another point, some cylinders require that a bottoming tap be used to insure the cylinder threads are tapped as far as possible. Of course, bin any crummy hardware and only use quality, graded bolts.