Dayton, I'm sure exactly what you don't understand, so I'll give a brief explination of the EBPV. The EBPV (exhaust back pressure valve) is a butterfly valve that International installed on the early 7.3 motors. It's purpose is to assist in engine warming in cold weather. The idea is that the trucks computer, which gets data from the thermostat etc., shuts the valve to hold back some exhaust, to help the engine warm up faster. There are a few glitches with this idea, which I won't go into. Anyways, that's the condensed version of the EBPV.
As for the position of the actuating arm. Well, that's going to be a tough one. I was having issues with mine, so I let it warm up good and toasty, then I unplugged the temp sensor wire. (that way I knew the stupid valve would be open). Anyways, I looked, and mine (which is a Ca. version truck, which are different in a few ways from the 49 states version), is connected somewhere beind the turbo pedistal. So, for me, and my truck, the linkage, is to the rear of the truck, not the front. Not sure if this is at all helpfull or not. (hopefully it is)
mike