69 Dart 340 Info Needed

Welcome newbie! Everyone has to start somewhere.I would say FIRST thing to do is try to get as many of the Specifications on the car as it is now from the owner. Such as Cam specifications,heads stock or worked on,type of intake, distributor type, type and size of carb,type of exhaust stock manifolds or headers all those type of things.
Once you know exactly what you have then you decide where you want to go and how to go about getting there. You may be able to do a cam swap,little work on the heads,nice food flowing intake,set of goo headers,have the Distributor worked over for max performance,good carb. For starters things like that. Just be sure to get as much information as you can when you buy the car so you know what you have and which way to go.