I put in a new 195* thermostat (the old one was a 195* and was complete) and flushed the heater core both directions until I got clear water both ways. Lots of rusty water, no noticeable chunks. Admittedly this was hard to do in 28* weather when the end broke off the garden hose. Topped off the coolant (I always drill t-stats if they don't have a vent)in the rad and overflow and took it for a drive...low heat output. The rad needed about another cup of coolant the next day...still low output.

The core was flowing clean water although I can't say if it was flowing as well as it should since my garden hose/heater hose mating wasn't optimal.It was a solid stream coming out but my water pressure is about 70 psi so it was spraying all over the place on the inlet side. Me and the hose were like

The cable adjustment has good tension and I can clearly hear the "klump" of the blend door opening and closing when sliding the heat selector back and forth.

It took a long time to get the feeling back in my hands and I likely will need a new garden hose come spring so right now I'm just going to think on this one for a bit. If anybody has a first gen Dakota and an infrared thermometer I'd appreciate if you could check your hose temps against mine.