EnduraMax Roller Lifters for Chevrolet Big Block Dart block. The pushrod seats are .300" higher than our standard Chevy roller . This new roller lifter is designed with a .300" higher push rod seat to fit Dart's BBC block. You won't have grind out your lifter bore for push rod clearance All EnduraMax roller lifters include "NBO" Needleless Bearing Option and "HIPPO" Hi Pressure Pin Oiling