<VV> Roller Rockers and Geometry

[Mikeamauro at aol.com]

I've got Clark's roller rockers on all three of my Vairs. In all three  
cases, to bring the roller back-n-forth across the valve tip, I've had to go to  
longer pushrods. The one that required the LEAST longer pushrods has the  step 
removed from the heads. One would have thought shorter pushrods would have  
been needed for this engine, but slightly longer was required to square things  
up. Is what I'm describging a normal phenominon with Clark's roller rockers? 
Thanks in advance,
Mike Mauro
(2) 110s and a 150