that is going to make a huge difference .....3.23 is a good gear. I have never had an automatic with 3.23 but my 72 swinger came with 3.23 and it is responsive on the street.
I need to start shopping for gears, I am fixin to swap in 3.91 into the wagon when I have money ..... I will probably end up with 3.91 open because sure grips cost $$$