1966 Plymouth Barracuda Help!

First off, welcome to FABO!! Secondly, congrats on procuring yourself a sweet little car!!

Now, what was the car doing before that you needed to change the coil? It may be that there is something up the line a little that is keeping you from getting spark! Like Karl mentioned, a service manual is a must, and Del will tell you the same! It's easy to follow along with Adele advise if you have at least a wiring schematic. These cars are really easy to trace wiring issues, there's not much to the wiring!

As for the overheating, it sounds to me like a blockage of some sort! As Karl mentioned, a check of the thermostats opening temp will tell you if and when it's opening! A shroud is always a good idea, and a flush of the system never hurts! It could be that the impeller on the water pump is broken and not turning, or the votes in the radiator are plugged! A bottle of Water Wetter could help some, it lowers the friction level of water and can help cool by some 20 degrees or more! Just thinking out loud here, but the fun of owning these cars is sometimes in working on them, and the satisfaction that you can actually "do it yourself",'a craft sadly lost on most new cars!! Be sure to report back on your progress!! Geof