The blocker rod simply firms up the shift because the fluid does not need to slowly "accumulate" enough to overcome the spring between the piston and valve body. The first thing I do when rebuilding a VB is to trash the spring and put in a blocker rod. Been doing that for 40+ years. For simple daily driving you're not going to need to get different servos, IMHO. I just install a Fairbanks shift kit that has all the components & blocker rod you'll need to have a nice shifting unit.