X pipe H pipe or side by side

I will try someday to post videos of my big block Duster in the burnout box both with and without the exhaust. The X and H pipe are both designed to promote scavenging from opposite side exhaust pulses, like supercharging by sucking on the exhaust. Without the X pipe I have to lay into the throttle for the burn out. With the X pipe and mufflers installed I have to feather the throttle to keep it off the red line! Better 60' with the X pipe too. I am running 3" pipe and my X is basically two 3" 90s with the cap of the bend cut off and welded together. Both H and X are designed to do the same thing but the X is more efficient. Before the X became popular I made U bent H pipes with the bend facing forward. This is what I still have on the 68 Dart and you will get nice low end improvements from a well designed crossover of either style.