"I second what Hy Stat says.
"I second what Hy Stat says.
Much of the torque goes into overcoming friction and other losses rather than stretching the bolt and creating the proper clamp load - for a clean dry joint.
Take away that expected friction, and you overstretch the bolt and POP! she goes. I've seen this where I used to work, and even tried it myself. Applied oil to the bolt, started torquing to spec and snapped the bolt like butter.
I suppose in the case of outboard heads though (haven't looked at specs yet)the clamp loads may be low going into aluminium, but as Hy Stat says the block threads could be in jeopardy."