Let's bring the pundits out! (your suggestions sought)

Well, I don't know exactly what I would do based on what it is exactly that I end up with. The future car may or may not have disc brakes to start with and I find it pointless to up grade the factory brakes for a causal driver. I am not knocking the bennifit of bigger brakes in anyway shape or form.

Same with ignition. Factory points or electronic is OK. Aftermarket material helps a good bit more in efficiency.

I'll take it from a point of a good running car that is fit for duty as is and as it was stock. So the 3 (or possible 4th) things I would upgrade right off the bat would be;

Fuel injection
Ignition
(which may come with the F.I. set up.)
Suspension
(Wider tires at all 4 corners for sure)
Exhaust
Even duals off of the exhaust manifolds is good.

The F.I. Manufacturer could be a F.I. Tech, MSD or Holley Snipper. A trio of inexpensive units that work well.
Read up on the systems to what they include and need.

Upgrade stock suspension can be OK! Depending on what your doing. Thicker T bars, quality shocks, anti roll bars, stock or not. All a good start and not bad stuff. Jumping up in the aftermarket stuff like a Gerst, RMS, etc... can get expensive quick and may be overkill for a around the town driver. But it is what you want to build the car into. All that have these set ups race about them.
(Talk to Abodyjoe about his RMS)

Exhaust. Be it duals from the manifolds or a full TTI set up from stem to stern, a otherwise stock 273 or 318 will pick up power & efficiency.

I left the ignition for last because (most) modern F.I. set ups come with timing control. However, if a F.I. set up is a little far away, a few basic parts can help what you have to start with inexpensively. If you have an electronic ignition, you could just swap on a MP Chrome box or equal with the proper ballast resistor and a good coil. Call it a day with new wires & plugs. Tune the carb crisp and it will be good to you.