GIBSON SUPERFLOW ROUND CENTER IN/DUAL OUT HIGH-PERFORMANCE MUFFLERS SuperFlow mufflers deliver more power, better torque and the Gibson "big block" sound at the tailpipe, where it belongs! Straight-through design and all-welded construction delivering maximum flow and increased power for improved low- and mid-range performance. Each muffler is fully baffled and chambered for better volume efficiency and unrestricted flow; never packed or screened and with nothing to blow out.