Motor Swap questions 88 cougar to 84 stang

[5.0 Fiend]

I blew the engine in my 84 5.0, and I have a couple of questions about swapping parts from my 84 carbed 302, to an 88 5.0 efi. I figure that to convert the 88 efi to a carb, I will have to install my mechanical fuel pump, put on my holley stealth intake (with Holley 750cfm) my main concern with that is, I am not sure if the fuel injectors run into the heads, or the intake manifolds, if they run into the heads, I will have to install my 84 heads, correct? If I am right, the 84 has flat top pistons, while the 88 probably has valve reliefs in the pistons, would this cause a problem (if I even do have to switch heads)? On to my next dillema, the engine has 75,000 miles, does not smoke, and runs good, I am getting it from a junkyard for $350, with a 30 day warranty. I can not mess with the engine for the warranty period, so is it possible to use my mechanical fuel pump with the efi setup (If I am correct you have to use an electric in line, or in-tank pump, right)? Last question, after my warranty is up, I plan on putting my 84 cam/lifters in the 88, (they are aftermarket, but not sure who makes them). What I want to know is, how hard is it to install a cam with the motor in the car, what is the easiest way to do it? If anyone knows the answers, please let me know, thanks.