I always have a spare set of extra ignition parts, (points, cap rotor, a bit of electrical wire & tape). Even though I have a Pertronix ignition, it's an easy reversal should it fail.
On long trips I carry a 1 gallon of water and a quart of oil. I always keep a small set of tools, flares, etc in the car. I've never carried canned air for a low tire, but for a long trip, maybe...
I make sure the spare has air before I leave, and verify all the lights are working properly.
For me, I always have some granola bars or similar food in case I'm broken down long enough to get hungary, and a warm coat. The emergency cooling system water is drinkable, and works for me as well.
I keep a slide rule in the glove box for computing gas mileage. Of course a cell phone, car charger and road service number.
Lastly, extra money in the event something breaks and it's more than I can fix on the road.
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