67 A/C heater box rebuild and install help

I shot some PB blaster in there and no go. Im thinking I will leave it and pressure test the evap with a garden hose and cap the one end. I bought pipe thread fittings, but they dont seem to fit. Anyone know what type of fittings those are?? Here is a pic of the galvanized sandblasted, painted and new insulation and foam gasket from Detroit Muscle Technoligies.