NHRA pulled all 14 of us over at Belle Rose and pulled a valve cover. They placed a stock valve cover gasket on each head. I just know my results were OK as it sealed to stock head and VC holes were intact. I can't speak for others but I am pleased they are checking and hopefully removing spacers if they exist. I presume you can have a spacer but stock iron should be under it. Low car count could be because Snowden and NHRA intel leaks. Pigs may fly???