Are you running a stock reed petals on the 87? 

I have had problems on some 1987s that have had the reed stops bent to increase the reed lift potential.  It does not help the power but will make the engine misfire at around 7600 RPM.  The engine behaves like it is an electrical problem or too big of a main jet.  It is reed float and can be eliminated by using thicker reed petals or a progressive type of overlay between the reed petal and the backstop.