I haven't been following the posts too closely with those that have recently pinned them open, but...
The system was designed for emissions. The primary, longer path was designed to swirl the air and get a more even mixure of air/fuel. Therefore, a more complete combustion. It happen to work well for torque too and was able to be tuned with timing for two peaks. Obviously, at higher engine speeds, the government doesn't care about emmisions so Ford satisfied both the gov't and the public.
So, I assume that you're going to have a really dirty system (cylinder, O2, exhaust) in a short period of time.
Aaron
