Big Block Rocker Shaft Shims

At Carlisle last year there was someone selling shims for Big Block Mopar to correct the valvetrain geometry. I remember him claiming that it is incorrect from the factory. Anyone know what I'm talking about? What is it supposed to be correcting? I'm at the point in my 383 BB build that I'm going to be getting new rocker arms soon and I want to make sure I'm getting what I need.


Is this him ?

http://board.moparts.org/ubbthreads...218&Words=B3RE&topic=&Search=true#Post7923244