[Hyper4mance2k]

Also, there is no real UEL vs. EL header debate because you don't honestly know which headers are EL. Are they EL in just runner length, or in volume length, or if they're just equal from the back of the valves with no consideration for variations in port volume.
Hell your UEL headers might work so well because they're actually EQUAL length in exhaust port volume, though probably not. Maybe just by happenstance they are equal for both banks, and that's why they work. You simply cannot make a scientific argument based on anecdotal evidence.
If you want to know why the ACE header works so well, they claim it is equal length in port volume and length from the back of the valves to the collectors. I can't confirm this, but if that's true, if you actually measure the runners they will not be "equal length."
One of these days I would like spend the time designing a 4-1 equal length header, equal in exhaust pulse length tuning at a specified RPM, with a true scavenging collector. However packaging something like that in this chassis would be horrendous.
You can actually do it without math. The easiest way to do it would be to run the engine with perfectly straight runners attached to each exhaust port, with a load, at the RPM you want to make peak torque and the hottest point on the each runner would be where you would have them collect into a scavenging collector. Of course runner size and a million other things come into account, but it can be done.
If you have a chrome header, install it, and run it on a dyno. Then take a look at it and note where the purple hot spots are. If they're not on bends, and other obvious flow restrictions, than your header isn't properly designed to maximize peak torque, across cylinders, at a specified RPM. Ideally, the runners should only discolor right at the collector and at the collector.