Help would be appreciated.

Brand new battery, all fluids changed. New ignition cylinder installed correctly.
All wiring/connections look tight/firm inside Instrument Panel...
But I get zero power when key in ignition. Not a single light or anything.

Is there some sort of master fuse/switch somewhere that I'm not checking?

Thanks in advance...

~Chris

are the battery cables connected properly? most of these cars are Positive Ground unless they have been converted to Negative Ground.

in other words, the Ground Strap which is bolted to the body near the battery, goes to the POSITIVE post of the battery, unless you know for a fact that it has been converted.

check all the Fuses at the fuse panel, one by one. They might look fine, but they can be blown.

when you open any door, do the interior lights come ON ? If not, the issue can be traced to the battery connections or to the fuses, these cars are very simple, there's no Master Fuse or Switch. There is a 3-position "dimmer" paddle switch which turns OFF the gauges lights, turns them on to Medium or to High. Another paddle switch turns ON the Map light or interior lights when the doors are closed, but it has no effect when you open the doors.