You know the combo demands more traction, especially in the sideways direction. And if you don't do it first, there's a good chance you'll slide that Dart right into the only hydro-pole within 300 yds, on the maiden voyage.
And besides, it will be the biggest expense.
To that end, if I may be so bold, I would attack the rear of the car first. This combo needs mini-tubs for big fat 15" rear tires, on a narrowed rear end with relocated HD aftermarket springs, slapper bars, AND yes, Air shocks; the kind that are actual dampers inside bags, for the very same reason we all did it in hi-school, which was;
1) at minimum pressure you get reasonable handling as a DD, and
2) you get the Ricky-Racer look on the weekend. Just make sure you leave an inch of suspension travel, so you don't hammer your shock mounts, off.
Next up for me is tricked-up power-steering box, a Saginaw pump, and a fat-rimmed, small-diameter steering wheel. I recommend 1.03 bars, a anti-roll bar, and HD adjustable front shocks. For me this was a no brainer for my driving style which seemed to be from one wipe-out to the next, for the longest time....... until I fixed the back end (I didn't do it first/my mistake).
I'd do the stoppers last, cuz the 10" factory drums are just fine at legal roadspeeds; and my choice is the KH 4-pot factory stuff. It's engineered for Mopars and has just flat worked on my combo, for decades with no fuss. and yes, I did put a booster on it, from an early F-body.
Oh wait, I did all that on my 68 Barracuda, lol.
Well except for, in my case, my factory tubs were already big-enough for 295s.
235/60-14s on the front look bigger than they are, but keep the front end where it belongs for non-competition car, in the which, your 340 should have enough power for rear-steer.. Get the hang of that with a clutch, 11.3 Scr, and you almost won't need the brakes anymore ............
BTW
The right air-pressure for 295/50-15s on tens is ~24psi. Which rides like a dream, until they are spinning,
