I believe that my '88 donor truck had it's original radiator still in place. I base that on this tag that is brazed on the top of it:
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This radiator has 4 rows and 53 columns, with ~12 fins per inch. It is 3 1/2" thick.
I went the cheap-and-lifetime-warranty route that tbrumm went, I bought a "Tough One" radiator from Advance Auto Parts. It was $230 shipped and comes with a lifetime warranty. For that price, of course it is a plastic/aluminum affair made in China, but, you know, all my other Fords came from the factory with plastic/aluminum radiators (including my '91 F150) and I've not had a problem, so they are maybe not as bad as some folks believe.
This new radiator has 2 rows and 69 (!) columns but the rows are much wider that the OEM rad such that the radiator thickness is 3". It also has 16 fins/inch, so, it sounds like an upgrade to the OEM radiator, at least from a cooling standpoint.
This brings up the subject of rows - I still see most folks refer to the number of rows as the end-all, be-all of cooling capacity, but, I have noticed for many, many years that most radiators now are made with less rows, but wider tubes. Now, I understand the deal about more surface area and such, but I just think it's not possible to just say "I have a 4-row" and let it go at that. My new 2-row is thicker than the 3-row that is in my F150. So I think the radiator thickness is as important to know as how many rows.
Anyway, the price was right, it has a lifetime warranty, it fit in place perfectly, and it's got more columns and more fins than the OEM unit. I hope it will be a good one for me.