Batman, I agree there are six studs restraining the cylinder head to the cylinder, but there are only four restraining the head and cylinder to the case. I think we can ignore those two 6mm studs on the side of the cylinder base adjacent to the cam chain channel. Either way, its pretty evident that stressing those studs up to only 37.6 ksi isn't going to cut it.
Armen, the acorn nut depth was on my mind when I did the quench project. That's why I stacked the copper washers. You will note from this post that I ditched the .090" copper washers and replaced with .220" steel washers. The steel washers are .130" thicker than stock. That compensates for the .130" I machined off the cylinder.
Using the degree method to tighten up the nuts is certainly and option, but it would require testing all four studs. Each stud is a different length on this engine. The longer the stud more nut rotation is necessary to achieve the same stress. It is a more accurate method.
Hotrod, I can't rule out the check valve entirely, but it sure looks like it was not the cause of my gasket failure. I'm thinkin maybe the check simply set up the right conditions to push the gasket over the edge. I've been testing the KrankVent, riding around with a vacuum/fuel pressure gage installed on the crankcase. I haven't observed any vacuum/pressure in excess of 2 psi. That's not enough to cause a gasket failure. I have a copper base gasket in there now and its 100% oil-tight.
I have a big problem with the test, the gage was not intended for high vibration application. I broke the gage. I didn't note any major pressure or vacuum spikes so I'm pretty sure vibration did the gage in.
The failure was so weird that it would be difficult to explain. I have it on a series of videos. If any of you are willing to review the vids and comment I would certainly appreciate it. I can post links to the vids so you can see for yourself what took place. I have observed a lot of gages in my career and have never seen one behave like this.