like the title says

I cranked it a few times while doing some valvetrain work when it occurred to me I should disconnect the power to the MSD box before I do that.

Now I have a terrible high rpm miss or stutter.. or something, the car hits what feels like a rev limiter and destruction is going on under hood

WB o2 shows good afr (carbed)

 

Pablo, Test your battery and see if its FULLY charged. I had a problem like that once and could not figure it out till some one told me about MSD being very battery voltage dependent.
My battery needed to be charged. After charging I drove the car down the street and my revs went from a "bad" 6000 to a nice sweet 8000+. Scared myself silly

 

well I ruled out the MSD, i just bypassed it completely and tested it, still have the problem, and actually the car runs a good bit rougher without the MSD so its actually doing its job

Thanks for the tip anyways... and I can just imagine that thing in your neighborhood cranked up to 8 grand.. your neighbors must love you Hehehe