I made the connections again. The blue wire on the positive solenoid post made the "Oil" light on the dash come on. Still no power to the fuse block or anything else. Big mystery?
The only heavy gauge wires leading in/out of the fuse panel are two on the left side - 1) the purple wire connected to the "S" terminal on the solenoid 2) a black wire routing to the "BATT" connector on the HEI distributor. On the right side harness from the fuse block is a heavier ga. red wire which appears to route to the alternator. All other wires are light gauge. All wires going in/out of the fuse block appear to be factory original.
Sorry, I don't have a 68 diagram but this one should be the same as yours, I hope this helps.
I just got a diagram for your 68 Camaro a fellow expert. I hope this helps you.
Here is page 2 of wiring diagram.