Well as I stated many times before, the OP didn't strip the threads, he broke the corner off the CAST plate. In the 9 years I have been on here I never seen a post where someone stripped the threads. They have always broken the CAST plate due to improper tightening of the screws.
Now with that said, last week I replaced my rocker box gaskets, there are 2- 1/4-20 screws in the center of the rocker arm assembly, around the 0-ring for the CR's, which have the same threads as the inspection cover screws, the torque spec is 15 - 18ft/lbs, yes ft/lbs, that equates to 180 - 216 in/lbs.
216in/lbs is 2X the torque of the inspection cover screws. I usually shoot for the middle and I did torque them to 200/in/lbs and I did it to 4 of them and none of them stripped the threads.
Most of the broken cast plates, and I'm willing to bet on this one, came from people seeing a small leak there and they crank down on the screw in an attempt to stop the leak, and what they hear is "tink" the corner breaking off. The rest of them have been broken when installing the screws incorrectly, meaning they don't tighten them down in a X pattern gradually.
I will say the BILLET plate that he makes now is superior to the cast plate, it will bend instead of breaking but you won't strip the threads at 108 in/lbs.
