I haven't completed my swap yet, but I have been researching and packratting parts away for 6 years. This is stuff I have picked up on this website, so I can't really take credit for it but feel it is good info.
For the record I am dealing with a '85 Ranger 4x4 with a Durasparked carburated 2.8 V-6 at the moment with a 3" bodylift so that is what I have concentrated my interest on. I have a 1978 302 supposedly out of a LTD... awaiting funding to be rebuilt. Tranny of choice for me is a 3 speed C4/5 mutant that I got preassembled and freshly rebuilt out a BII that was being junked. I like it so I can run the factory t-case... something you won't have to worry about anyway.
Older engines with the dipstick in the timing cover require a special dual sump fox body oil pan with the dipstick IN the pan. Later engines have the dipstick in the block... and non dipstick pans are much more common. Speaking of which, you need a dual sump Foxbody (79-93) Mustang oil pan. Somewhere around 83 or 84 they changed the dipstick location. You will also need the oil pump pickup to go with it and the main cap stud that the pickup mounts to. Pretty much it is a main cap bolt with a smaller stud sticking out of the head.
You might think about putting a gasket set in your 302 while it is out if it has been sitting for awhile. In other words there will never be a easier time. If it is a older engine like my '78 302 with big chamber low compression heads, later model heads (like E7's) are pretty cheap while it is out too. I got my E7's for $80 with a set of pushrods and should bring the compression up to a halfway respectable number.
Serpantine front dress fits the best if you have to get it, it fits closer to the engine and leaves more room for a mechanical fan. It also sets the accessories closer to the engine, really not much wider than the base engine fully assembled. I am going to try a '78 LTD V-belt setup, dunno how it is going to work but it is what I got and being a tightwad I am going to give it a whirl... staying with a mechanical fan if I can.
I have a new alternator on my 2.8 and am going to try to use that on my 302, no diffinative results to report.
I am going to use first generation 4.0 Explorer automatic radiator, they fit nice and are a common part if you have to replace in the middle of nowhere. Depending on how hot your engine is built you might need bigger or fancier radiator, I am staying fairly close to stock so you are on your own there.
Exhaust depends on what you have for headers/manifolds. Fox headers require header mods and/or a frame notch... all around ugly. SN95 driver side fits nice but pass side aims at the frame. Factory "log" manifolds and Hedman 88400 headers are supposed to fit nice. I am going to run custom bent true duals (I like how they sound) off the manifolds (or headers if I find them)
I am going to use 5.0 SN95 engine mounts as mentioned in the tech article.
For wiring, if you are staying carbed I would duraspark it if it isn't already. My truck was halfway set up for Duraspark from the factory, I converted my 2.8 to it so it will be plug and play for me when it comes to drop in the 302. I got the pigtail that goes between the brain box and the distributor from a 400 V-8 that died in my dad's truck. I got the DS box and other plugs from a junkyard out of a 300 I6 F-150... parts are pretty generic for the DS system. It is all living happily with my 2.8 at the moment.
You don't want a link but I am going to chuck one at you anyway because I don't want to type it all out, and no offence but pictures are about the only way anyone can understand it anyway.
http://www.therangerstation.com/tech_library/DurasparkII.html
For EFI, I don't know anything so I won't say anything other than staying with a system closest to what year your truck is will probably keep it the simplist.
If you stay carbed look around about what to do with your high pressure fuel pump(s) as far as a fuel regulator goes. I don't have to worry about it with my truck, but I do know it will be an issue if you do stay carbed.
I think I caught most of the high points, but remember... the devil is in the details. I don't think any two swaps ever turn out exactly the same, there are no "insert bolt A into slot B" style instructions out there that I know of... there are way too many variables.
Hope this helps...