The cylindrical thingy is the solenoid. I dont know if you have an HEI didtributor or not. If you do, you should have the (+) cable hooked to the largest post on the solenoid, then 2-3 fusable links on the SAME post. The small post on the inside edge,(next to the block) marked "s," should have one wire on it. Factory color is usually purple.
If you have a point type distributor, the other small post, marked "r" will have a wire going to the (+) side of the ignition coil. If you have electronic ignition, this wire is not needed. In fact, newer solenoids dont have the R post.