same old problem--no heat

[Libby]

I asked about this problem earlier this year; now I'm back, with the same problem. My 67 coupe is COLD. My mechanic just replaced the radiator, the thermostat (a 180, up from a 160), the heat/temp/def cables, the plenum, & flushed the heater core (it's only 2 years old). I've got barely warm air hitting the windshield, and mostly cold air at my feet. He says he checked the hoses & heater core, and there were no clogs &/or gunk. I'm wondering if the heater core could be bad, even tho' it's not very old. Is there something he & I are missing? I mean, my beast has never been terribly warm in the winter, but this is just not right.