Starting a BB Duster project

The car has 4.56 gears in it now which are too steep with the 512 that I decided to go with. The car was built from a collection of parts that I had and I figured the 4.56 gears were too steep but the rearend was already built and so I just thought I'd see how it worked. It works but gets a little old after a while on the freeway. The 4.10 gears will help.