I have a 69 super bee 383 727.motor has a mild build.it has 3.23 open rear.i am going to put in a sure grip and go taller on gear.i do a little hiway driving but want more low end.thinking 3.55 or 3.73.anybody with experience going from 3.23 to either of these?3.55 enough of a difference?thanks for any opinions.david