Your link works, I looked at it, the compatibility chart shows it fits 22 vehicles, all Tri 5 Chevrolets.
The link to the installation instructions comes up with nothing available.
The pictures in the listing do not show a typical triangulated 4 link like GM or Ford have used for decades. More like a splayed foot 4 link.
The listing is too skiffy for me to consider it, I get an itch between my shoulder blades reading it.
It does say, at the very top of the listing "Upgrade Today! Coil Overs Not Included, Save $$$!!"
i couldn't find anything using that link, but the "johny law motors" set up i mentioned listed a 38 plymouth as one application as well as a ton of tri-5 chevys and almost all a,b & e body mopars as well, using the same picture to describe the same basic kit. i didn't notice about the coilovers not included. with that being said, what is the difference between a "triangulated " and a "splayed" 4 bar setup ? i thought those were one and the same ?