Ford Mustang 2011-2013 V6 3.7L, 2½" Stainless Steel Pro Chamber to MAC Long Tube Headers  The MAC Patented Pro Chamber™ has made the current intermediate systems obsolete all together. Split (one each side) manifold or exhaust headers on any engine, need to be balanced to each other. On a V8 motor for example, the exhaust pulses enter respective collectors at uneven intervals of 0-90-180-270 degrees of engine rotation. This process hampers the full benefits of any exhaust header system or manifold by the long intervals between exhaust pulses. Balancing of exhaust gases in mandatory for optimum power. Balance tubes between exhaust, on opposite side, helps transfer exhaust pulses for side to side to smooth out the exhaust pulses and flow. This results in more Power and a broader Torque band.