I assume you plan to do it yourself. Always look at the interfaces.  Connections, if you will.  That is where most problems occur.

It could be difficult, depending on where you live.  but try to find a car in a junk yard with the 5.0 still in it.  Hopefully, you can find one with the trans type you prefer.  Then take the whole drivetrain from radiator to/including rear end. (You might want that 8.8 later).  Wires/cables/computer too.  Don't cut anything.  Keep everything connected to the running gear.  Unbolt/disconnect them from the body.  You would be surprised at how much stuff you then do not have to buy.  Even worn-out parts are useful to show you what to buy.  Nuts and bolts, too.  Newer cars have some metric connectors that you might need.  You can dicker for a better price, too.

I've done that a few times with friends' builds and they & their mechanics thanked me afterwards.  

I used the following sites to install factory efi into my car:
My donor was a 92 mustang Gt.


http://www.veryuseful.com/

https://www.jegs.com/InstallationInstructions/300/397/397-M-12071-A50.pdf

http://www.midnightdsigns.com/james/

https://web.archive.org/web/20110430180836/http://fordfuelinjection.com/

I will say this:  If you can find a complete EFI 5.0 from an 88 to 93 Mustang or a Mk VII Lincoln and grab all of the under hood harness, and all of the sensors, then put it together as a STOCK setup as it came from the donor with only a couple of minor modifications...removal of the secondary air injection and maybe removal of EGR, take your time and make sure the harness is electrically sound, and do the fuel system properly.  I
It will very likely server you very well for as long as you want it to.  In my experience it when you decide you want a hot rod that the problems will start with the Ford EEC IV EFI system.  It can be tuned and modified and hot rodded and mad to run just fine, BUTT (TS&T) the learning curve for that was just too steep for me. 
I drove our 66 with Ford EEC IV EFI from 06 to 2013, nearly 20K miles, to Texas a couple of times, to Kalispell, and all over Colorado including the top of Pikes Peak (14115 feet) with ZERO problem.  Absolutely reliable, no stink, 22 - 24 MPG.
Then I decided I needed MORE.  Better heads and more cam.  That when My problems started.  Studied how to tweak the computer for a year.  Bought a tuning emulator and softwear.  Downloaded calibrations. 
I made it run and probably could have made it run really well but I just got tired of messing with it.  Meanwhile my friends whom I had helped with a stock EFI 5.0 in their 64 Falcon kept on enjoying their car with no problems.  Every time I watched them bump the starter and drive away I was jealous.
So decide what you want.  I you want near total reliability in a car you can drive anywhere at any elevation without issues.  No fuel stink in the garage (my wire's desire) and easy maintenance with reasonable economy and are willing to take the time to do a proper install, go with (Ford) EFI.  Otherwise bolt a pot on it and be happy.  Properly tuned, it will serve you well that way for anything you want to do.

BB1
 

The biggest issue you can encounter is the age of the wiring on the EECIV cars.  I like the system, understand the system, and would prefer it for a swap due to its simplicity and lack of a complicated and integrated emissions system.  The engine harness is reproduced by Ron Francis.  I bought one for my '89GT and its good quality.  I think they also offer a swap harness that goes from the engine harness to everything else.  Obviously its not plug and play, but its probably better than trying to parse through a greasy, old, potentially damaged stock harness. 

If you are going to keep it stock you won't need to tune it.  Unfortunately 225HP just isn't what it used to be.  If you're going to modify the engine you're either going to need to find a local tuner or learn to tune as BB said.  There is a TON of resources on the net for this, but it can be a LOT to learn, especially if you are relatively new to EFI. 
 

My Buddy in high school had a 68 hard top Fairlane.  His was light blue with a white top.   He had it jacked up in the back with Cragars all the way around.  Had a 4 speed with a nasty 302 and tunnel ram.  That car flew!
Loved that car!  

The pinout chart in the Jegs link to the manual and very useful’s wiring diagram made it easier for me to figure out how I wanted to modify a factory harness.

As some may know, Ford wasn’t consistent on color codes for 86-93 efi harnesses.

All necessary information is shared by many.