OK so heres the problem, my stock valve covers wont clear my RR's so I buy taller ones. Now the damn alternator wont clear the valve covers. Does anyone know what the hell is going on? Oh yeah if you need to know its a 93 lt1.

 

What brand/type of rocker arms are they? I'm 99% sure that the interferance is with the internal supports of the covers. The stock covers can be modified to accept wide body rockers. Your new covers can be fitted by grinding a couple of spots at the back of the alternator.

 

This isn't really advanced tech, but the above answered your post.