The plastic cover inside the passenger side compartment houses the heater core and also the a/c drain. My question is, is there enough clearance between the bottom of the plastic cover and the bottom of the heater core to drill a hole and screw in a brass fitting to attach a new a/c drain hose? Due to an exhaust leak, the original plastic drain was melted and there is not enough room between the firewall and the back of the motor to clear it out. I routed a steel flex hose through the firewall and to the bottom of the plastic cover but I don't want to drill a hole and end up drilling a hole in the heater core. With the brass fitting I want to use, I would need about 1/2" clearance.