The canister is a vacuum reserve tank for the cars with A/C. The doors and motors of the system are operated by engine vacuum. The tank held vacuum in reserve so that the settings would stay under low vacuum situations, ie; heavy acceleration. Without it, the doors and motors return to their resting position, which IIRC is full defrost. I don't remember which nipple is which, but one will go to the vacuum tree on the back of the manifold. There are two vacuum lines coming out of a grommet on the firewall by the heater hoses, one goes to this canister, the other to the hot water shut off valve on the hoses.
The plug in your air cleaner housing is blocking off where the crankcase breather and filter are supposed to be. Looks like you have an aftermarket set of valve covers.
Looks like a custom ignition setup and that is the weirdest looking starter solenoid I've ever seen. Seems that you are missing your voltage regulator, unless it's been moved?
