I have 2 sets of NOS Thomas Magnesium rockers for a GMC but have never used them on any of my race engines. They were for both intake and exhaust. The stock adjusters were supposed to be used with them. I was always leary of using them because of the surfaces on the shaft. The push rod hole becomes a problem when you go to larger diameter push rods. I believe the problem would start with the 3/8" ones, 5/16" might make it.

216.158 MPH 12-Port 302 GMC on 70% 171.0 MPH 302 stock head on gasoline 7 years later