One thing about "dropping" a C-body, is that it can have some challenges, if not a complete re-do of the suspension. Now, I believe in the Drydock about 10 years or so ago, there was a guy in KS that put a 4-link on the back of his '66 Newport 2-dr hardtop. As it turned out, easier to do that I suspected. Using the orig front spring eye location for the pivot point of the lower arms, for example. Don't recall what it took on the front, but the car ended up loosing ALL of the Chrysler-trademark TorsionAire feel, which is one thing that makes them so much better and nicer to drive, especially with HD shocks.
The front and rear body overhangs already might have some "approach/exit" issues with the rear bumper and tail pipes as is, so anything lower can take some additional care in how and where the car travels. Which, to me, detracts from the total driving experience.
On my '77 Camaro LT, I had OEM Z/28 cat-back pipes put on it. When the resonators went away, I shopped for newer mufflers. Ended up with something "larger" in diameter. I wanted the system "clamped, not welded", which they did, against their desires. Their clamps stretched, but on the way home, I noticed that even the slightest bump caused the NEW mufflers to hit the pavement AND the gentle apron on my driveway. I figured I'd just reposition them, which was problematic. Ended up getting the correct replacements under it at another shop. That was ENOUGH experiences with a factory low car and saggy exhaust systems! Even at factory ride height! Ever notice how some of the factory ground effects had a higher point in the middle of their rocker panel pieces? Otherwise, the whole thing could end up in the street!
To me, ANY OEM Chrysler suspension is at its best when it's at factory level ride height. Plenty of wheel travel to better absorb bumps/dips without bottoming out. Best with HD shocks, too.
Just some thoughts, from my own experiences.
Enjoy the project!
CBODY67