Name that part.....

[BigCountryx]

I'm sure this is an easy one for most of you guys, but what in the world are these things? I've searched with no answer that I could find. This is on my 70. The thing on the firewall looks like some kind of relay, but for what? Best I can tell, there is a red wire that comes from inside the cab and goes to this relay thing. A black wire comes from the 2/3rd gear yoke on the trans (3 speed saginaw) and goes straight to that thing in the second pic. Then there's a blue and a green wire off of the relay thing, the blue is the other wire to the second pic and the green goes to the temp sensor on the therm housing, clear as mud huh. The piece in the second pic has a vac line from under the carb, it's mounted to the intake manifold and it's attached to some apparatus on the exhaust manifold.