X & H pipe vs straight dual exhaust

..Larry Sheppard,Mopars' head engineer for their Direct Connection program says an H pipe
produces no increase in hp.An H was installed on some factory models to quieten the exhaust
and allow the use of less restrictive mufflers.
...the H should be smaller than the exhaust diameter and be located 12 to 16 inches back.
...i have no experience but it's hard to believe a 6 inch piece of pipe could make any power?