After a long drive (300 miles) I noticed that everything cut put for a split second when I dimmed my lights. Luckily I was almost home and when I shifted into reverse everything shut down again, not long enough to stall the engine but I wouldn't want to drive anywhere until I get this figured out. Thnaks in advance for any thoughts.

Also check:
1. All fuses and relays. Take them out one by one and clean the contacts with emery cloth.
2. Check the ground cables, battery-frame and engine-frame. Clean the contacts and reattach. Corrosion is especially a problem if your car has lived a long life in a humid place or a place where the temperature varies greatly and you experience condensation.

Drove the car today and all seems fine. If it was a relay or ground wouldn't it be continuous?

Good question. Humidity can change conductivity, especially if there is some corrosion or tarnish on some of the contacts. My experience with electrical problems on old cars is that 99% of the time, the problem is caused by bad contacts or bad grounds.

The exception is when the wiring is disintegrating as with the mid-1980s 240 cars. In that case, you need more than clean contacts!

Check the cables to the battery. Clean off any corrosion and carefully inspect the red wires for cracks.
Then with the car running, jiggle the key to see if it is loose and eliminate the electrical part of the ignition switch.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Ok, will do. I'll start this process later today and let you know how it goes.