Sounds like the water pump is suspect or your cooling passages are clogged. I don't think it requires something special, but I got ours from our local parts house. I deal with a guy there that knows old Mopars, plus I have the parts manual so we cross the numbers. But most just he just knows off the top of his head.
Speedo cables, I have a link to Lokar:
http://www.lokar.com/product-pgs/throttlecables-kickdowns/tc-kd-pgs/throttle-cables.html
If I remember correctly, though, my local guy got me the right one for ours (I brought in the old and he matched it). Our cruise control, which is an add-on and not factory, has never worked properly so I think we just bypassed it.
