Looks clean. But where did you get the 3.55 gears? I am pretty sure that nobody makes a 3.55 gear set for the 8.5" 10-bolt GM rear. Common ratio choices are 2.73 3.08 (stock Impala), 3.23, 3.42, 3.73, and 4.10.
Not criticizing - just trying to help you with info.