300zx tt z32 coolent drip

Car just had headgaskets replaced. I know for a
fact they were torqued to spec. Car runs good and
doesn't overheat like b4 but it has a very slow
coolent leak. A drop every few seconds when car is
warm at idle and maybe leaks more when under
load but not sure. Looks like it's back of the motor
in the middle. It's drips off the oil pan and where
the motor and transmission connect. Heater core
hose maybe? Thanks for any help