First thing to do is write out a plan so you don't have to re-do later, something you are going to do now. AKA slants are not gonna have decent brakes, if you want more power. So decide what you want to do. Does it have disc? Doubtful. If not figure out the route you want to take, AKA upgrade to the big bolt pattern, and so on.
You can do really well with stock like components. The basics are you want to rebuild the front suspension so everything is tight, and check the steering box and replace/ fix it if necessary. Look around and ask here, because some brands, including Moog, may not any longer be the best. Unless you know the history of the car and a recent rebuild/ upgrade, I would replace EVERYTHING. All rubber bushings, the lower arm pivots, ball joints and tie rod ends. Take a GOOD look at the balls in the idler arm and pitman. Take a GOOD look at the steering column coupler.
Buy some decent wheels and tires. Here again you want to do this AFTER you've improved the brakes, because you may have changed the bolt pattern. Buy some decent shocks. Buy either an OEM or aftermarket front anti sway bar. THAT ABOVE ALL ELSE really helped my "was factory" 273 67 Dart. Look around for some stiffer T bars. Even 318 stock V8 bars would likely be better. MEASURE them AKA calipers. Or, take an end wrench and measure yours so you know what you started with.
Rear springs. I did pretty well with mine, "lucky." I just took apart some A body leafs, took mine apart, and made new packs using the longest leafs from the two packs. I think I added either 1 or 2 at the bottom more than I had. I could not believe it came out just right.
Don't forget to examine/ replace the rear spring bushings AND DO NOT USE extended shackles.