72 upgrade

Just my IMO, but 4 BBL is not the way I would go at all for what you name; daily driver, mpg, and performance. As said, the engine breathing is not there for a 4 BBL to be used; a 2 BBL is better for general driveability and even the 1 BBL is not being used to full breathing at lower RPM's.

If you want performance improvements, then
- start with a mild cam; if you stay with a torque cam (more lift with a wide lobe angle), then you can keep the mpg OK and still have a good performance improvement at low to middle RPM's with a small carb.
- shave the head .050 or so for an easy CR improvment; the stock CR is just at that point where even a .5 point CR increase will make a big torque difference

For MPG, look seriously in the 4 speed manual with OD that came in the Dart Lites and Feather Dusters. That will give you the best mpg improvements you can get in that car, and yet you will be able to use 1-3 gears for fun. (I drove one for years....28 mpg in the interstate at 65-70 mph wiht a 2.76 rear axle)

I don't live that far from you so when I get my new torque cam in in a few weeks, you can visit and see the difference.