I don't have a before and after. I swapped from a v6 to the 5.2 and built the exh when I did the swap.
It's possible smaller exh could make it quicker. It went 13.27 @ 102.xx at 3800 lb race weight, so it's no slouch. 8.8 cr and small magnum roller cam 210/220 @ .050. It dynoed 290hp/286tq...