it seemed like the 26 (new version) was too tall.
Mopar 18, 20, 22, 26 and 28-inch-wide radiators are all the same height (within ¼”) – except for the older C-body’s.
What makes the difference in installed height is the side straps – which can vary from body to body type or year to year (mostly early ‘70’s and older).
If you try to install an ’69 B-body 26” radiator into an F, M or J-body, the core support bolt holes will not line up and can place the radiator higher (or lower) on core support once bolted in.
In those cases, reusing your old side straps will fix that problem.
The same applies to fan shrouds. All FMJ vehicles used one of two different shrouds - which are different than all other car body types. One for the 26” wide radiators and another (when used, that is) for the narrower fan shrouds.
My ’77 wagon with an 18” radiator was manufactured without a fan shroud.
I mentioned I have a few older radiators. I also have a lot more that are "known leakers” which were saved so I can hang onto the side straps and tanks (like the original radiator from my '86 Fifth Ave).
In most cases, I can drop a 28” wide ’68 C-body 4-core radiator into my FMJ by only replacing the side straps (or having a radiator shop transfer them over) and also drilling new bolt holes 1” closer to core on both sides.
Older pickups and older C-body’s are the only ones I know of with 28” wide radiators.
I should also note core supports for almost all body types (and trucks) fall under two different classes – wide (26 and 28”) and narrow (18 through 22”).
The side straps are different for each width radiator – so you can’t get a ’18 side straps to fit onto a 20” tank without also moving (adding new) bolt holes over as well (if that makes any sense).
This picture is a typical Mopar brass radiator. The red arrows point to the metal straps which are soldered onto the radiator (in areas marked by purple lines). If you have access to a wide soldering iron or a low temp torch – a person can replace these themselves. I’ve tried, but soldering /welding is not my strong suit (so even soldering two wires together look like something a 5-year-old might do).
BudW