Bob there are several plugs you can remove from the engine to route the heater line in, one is on the top/front on the other side of the thermostat OPPOSITE the feedline to the heater core. The other is on the side of the block were a "aftercooled" 4bt would have the return line, I used the one on the top. Oh and by the way all my p30 vans have had the return line going directly back into the radiator! As far as the intercooler working and keeping good boost I couldn't tell you yet as I havent made it out the drive way yet!