Tom, I'm using a Griffn 26242x in my red 66 GS. Fits and works great. Bought it about 10 years ago.
Since then, there have been reports of quality issues of Griffins but don't know if they've been resolved.
Mine has formed tanks with the ribs, looks like original style. Now tanks are made with flat plates...... that may affect fit.
It's a universal sized radiator, fits popular applications such as mid 60-70's Fords and later Mustangs..... there are other choices out there. No internal oil cooler. Cost under $200. Also avail with wider tubes at extra cost.
https://www.summitracing.com/parts/gri-1-26242-xSummit has other brands avail, use their radiator selector to choose one that's 27.5" wide and a max of 19" tall:
https://www.summitracing.com/search/universal/yes?N=4294949245%2B4294951518%2B4294949208%2B4294949197%2B4294919516&PageSize=100&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=Aluminum Radiators
A popular application for this size rad is an '86 Mustang. Should be lots of options out there.
For shrouds, fiberglass repos were made by Kirban Performance and sold through other vendors. Don't know if they're still being made.
I've modified a 300 shroud to work on a GS..... turned it upside down and trimmed an inch or so from the fan opening.
It got destroyed by a flex fan that lost a blade.
I don't even use shrouds on my cars since they run fairly cool.