MOPAR suggested reading?

Ok folks. I'm new to the Mopar thing cuz my 14 year old picked a '73 Duster as our father/son project. And my extent of knowledge on Mopar is what I got from my buddies dad back in high school who had an Aspen R/T. He said....."Always keep one of these in the glove box." He was referring to that little ceramic block. A resistor, I think? So is there some reading material that you folks can suggest that will bring me up to speed? :read2: