I looked through
www.rockauto and the Monroe website the other night. Seems that the Monroe front and rear shocks all have a 1 3/16" piston diameter, but what I'd consider "unknown valving" (of sorts). All now-major shock brands seem to have the same descriptions of their products and some sort of speed-sensitive special valving. ALL shock valving has been this way since waaay long ago, but they now describe it as something new, high-tech, and desirable. Which tends to make me think that they are all the same internally, just painted differently? KYBs would be their own product, I highly suspect as I don't believe they have been bought and sold multiple times between the middle '60s and now? Just a suspicion.
In the shock's specs, you can determine the full-extended length and also the full-compressed length. As most 1960s-era suspensions were designed for "ride height" to be basically in the middle of the shock's travel, then measuring the shock's length (cL of bolt hole to cL of bolt hole) might give an indication of spring sag on the rear?
As I recall, if the C-body had factory a/c, they got upgraded torsioin bars (as determined by their spec diameter), which would make the "HD suspension" on the front be comprised of just "High Control" shocks, best I can tell, on factory a/c cars. Adding more pre-load to the torsion bar will make it a stiffer bar, from my experiences. But within the stated height specs, not a lot of difference.
There were actually 3 torsion bars, regular, factory A/C, and heavy duty. I assume mine are the A/C choice.
In the realm of shock valving, most of the resistance is on the extension side of things, rather than the compression side of things. Independent of any internal gas charge features.
When I needed front shocks on the '67 Newport (after I bought it in 1981), I wanted something equivalemt to the old Super 500 hd shocks, as the Gabriel Striders (adjustable) had been discontinued by then. Their then-new RadialMatic shocks were their HD shock of choice at the time. I was not impressed with them as to their stiffness, but they seemed to work ok for what I was doing back then. I'm not sure how their current MonroeMatics or OESpectrum shocks compare to the earlier shocks (valving wise) other than the size of their internal pistons.
The reason I mentioned "tire pressure" was that I know that Chrysler sped'd different tire pressures for the wagons than sedans. Although the wagons might be a bit closer to 50/50 weight distribution with that extra weight over the rear axle. Which, on the wagons, included a very low front tire pressure, by comparison.
Just some thoughts,
CBODY67
