Making it a better driver

So, after three years of talking about it, I finally went and picked up my wife's grandfather's 74 Dart Sport. It needs a fair bit of work to make it pretty, but it runs o.k. and has low mileage. I'm starting to make my list.

The first questions coming up are driveability. I don't need a 12 second car, but it would be nice to have a car that would comfortably cruise above 80. This one doesn't seem happy about 60. What can I do to make my 225 a better road vehicle?

Based on what I'm reading, I suspect the answer would be:
-Upgrade the transmission so I have something with an OD,
-Electronic ignition,
-Something with intake and exhaust,
-(Suspension and brake updates are for another page but are most certainly on the list!).

The threads I've seen around intake and exhaust appear to be folks looking for real performance. I have apparently, at some point, gotten old and think that, for this car, that's not what it needs or wants to be. So, I'm looking for fun, comfortable, and reliable. The fun I plan to get through suspension stuff, comfort through the interior, and reliable (and driveable) through the drive train.

Thanks for you help and I'm glad to finally be starting this project!