Chryslers, with (what used to be) a good HD shock, were NOT about "float", but firm smoothness. "Float" was what GMs did, back then.
I never did get any for a Chrysler, but it was said somewhere years ago, that the best shock for a Chrysler (like in the '60s and later) was KONI. Reason was that the guy that owned the company drove Chryslers, so they got more attention to their turning than shocks for others brands might have. Never did confirm that, though.
I have used KONIs on my '77 Camaro for many years. The work well on that car, BUT tire choice can make them act differently! I started with BFG Radial T/As on it, then went to a Pirelli P77. The Pirellis were smoother tires and were also "H" speed rated, with assymetrical tread and compounding. A "low bounce" rubber, they claimed. Those tires absorbed so much of the little road imperfections that the valving must have thought they were on smooth Interstates all of the time. I never could get them adjusted firm/stiff enough! When I went back to the Radial T/As, that gutsy feel returned, which was what I liked. Smooth then they needed to be, stiffer when they needed to be. And they were adjustable, too! I saw some listings for a '66 Chrysler application once, but never did order any.
I had a friend who put Bilsteins on his '77 Z/28 and it was strange, compared to the KONIs, it was softer riding, but easier to make the rear end slide in a corner. Weird!
I put some Gabriel Striders on the front of the '66 Newport, back in '73 and they worked great. Still had the Chrysler HD shocks on the rear. Adjusted them one click "firm" and they were fantastic in ride and handling. But they left the market years ago. Those shocks are still on it, as it "lays in wait".
In one respect, I'd be inclined to put some Monroes on it and call it a day. They'll be decent, at least. The "Monroe-Matic" would be the choice, I believe. Seems they've all got the larger piston size now. Otherwise, some KYBs.
In the last couple of years, everybody's advertising "speed-sensitive damping", which is what the valving does anyway. Kind of makes me wonder if they're all not the same internally, other than the KYBs, anyway.
CBODY67