Engine rough at high rpms

[webbslinger]

I just stumbled upon this thread from 8! years ago, and see that I never posted what the problem turned out to be. It was a broken inner, or secondary?, valve spring on the #2 cylinder that must have broken on the dyno.
The spring was replaced in the car, and the engine has since run flawlessly for 40,000 miles. Sometimes you get lucky.
My apologies to all of you who offered advice and encouragement. The fix came a month or so later and I forgot to follow up.

[512BB]

And the prize goes to Chancer, who passed.

Leslie