Ouch. Well, just heard back from the radiator shop. Heater core is bad. He attempted to find a source to replace what was necessary, but no one makes heater cores in that size. So, Obsolete Air it is. $304.99 later...and it appears I have a brand new heater core on the way. On the upside, my evaporator is good and he's going to flush that out for me so will be good to go whenever I get my A/C set up.
Received all my stuff from DMT yesterday and looks good. I hope to get the heater boxes cleaned up this weekend and new seals installed and ready for the new heater core. It'll be a good diversion from removing the old glue and readying my roof for the new vinyl top and attempting to get the rest of the dash removed and cleaned up and painted. Moving along....
I'll post a pic when I get the heater box done.