There must have been something wrong with the Windsors that Kdawg got because they are great motors. There is tons of after market for the Windsor as such it can be built as mild or as wild as you want. IMHO a mild rebuild won't be to much for a 2wd Ranger, it may need a little help hooking up but not much. A wild motor, on the other hand, is way to much for a Ranger, at least if you want to put it on the street. Now it you decided to build a build something in the middle you will need to be looking into items that will assist traction, but I still wouldn't call it to much.
It really would depend on how much work you want to put in to the build. If you want to bolt in the motor and go type set-up go with an F-150, as there's a better chance of it already having engine mounts, transmission, rear end, radiator, etc. that will work. If you don't mind having to get together the extra components then go with the Ranger. When I Say extra components for the ranger you will need at least the following; motor mounts, headers, transmission, transmission mount, rear end, radiator, and clutch pedal system if you go manual transmission. Also keep in mind that with the Ranger most of the items you need will have to be modified in some way, and some of them will have to be custom built.
I'm not trying to scare you away from the Ranger build, no doubt it would be a fun truck, I just want you to under stand there will be fair bit of work involved then would be on the F-150. If you feel that you can handle the work then go for the Ranger, if not then get the F-150.