may seem obvious but its not to me so....does the pump draw air from the h-pipe or does it pump air into it? also, that pipe that comes off the back of the heads, is air going in or coming out?

 

air blows into the back of the heads and i think it sucks the gases out of the h pipe and blows them into the back of the heads where they are returned bacn into the cumbustion chamber for a more complete burn

 

I just replace the smog pipe and two of the check valves and what I've read and been able to determine is that air is pumped into the H-pipe to allow the cats to burn hotter so it can burn off any excess unburned gasses before it exits out of the exhaust. In regards to the heads, air is going towards the heads, not sure exactly the purpose but I think it flows in that direction.