302 engine cranks but won't start, what's wrong?

you need to test for proper fuel pressure and spark , any prior problems don't matter and are only assumptions , are the injector(s) firing ? If you have fuel & spark then that leaves compression , how old is that truck ? Is the timing chain ok ?

The truck is an 87 Ford F150 XLT Lariat 4x4 with with a 302 V8. And as I stated the fuel pump in the gas tank was replaced right before I bought it I replaced the fuel pump on the frame and the fuel filter. Then replaced the alternator and the battery. The only reason I stated those things is because those are all things that I have done to the truck personally or I know have been done to the truck. I also know that you need compression, Spark and fuel for an engine to to operate correctly. As for the timing chain I haven't gotten that far into the motor yet but when I put a new alternator on I did put a new serpentine belt. I just know from everything that I've read or what or even heard about this truck in general there are a few main things that causes problem and I listed them in my question you're the first person however that is suggested the timing chain. Now ask for the three things that I know you need to make the engine run I know I'm getting fuel as I stated I changed both fuel pumps, the one in the tank, the one on the frame, the fuel filter and I've done a fuel pressure test. And as I stated I done all of that approximately 6 months ago and the vehicle was running fine until the alternator went out about 2 weeks ago I've been replaced the alternator and the battery the truck was running fine again and to approximately 4 days ago when I was on my way home from work and it died and wouldn't start back and after doing fuel pressure test and so forth I've determined that it is getting fuel but no spark my question is and was where would be the best place to start for out of the things that it could possibly be which would be my most likely. After being in several forums and watching videos on YouTube and going through my Hanye's manual several times I keep coming back to the same things which are distributor, ignition coil, TFI ( Thick Film Ignition Modular), ECM, plugs & plugs wire, & Relays etc. And another question was if it turns out to be the distributor with this model of Ford would it be better to replace the Stator and the shaft or just the Stator. I do appreciate your help however I don't think it has anything to do with my timing chain if all else fails I will check that. I guess basically what I was looking for or asking was has anyone else out there that had encountered this same problem with this same generation Ford and/or motor the 302 V8, what they found to be the problem. I'm sorry though I was only stating the other things that have been done to it like the fuel pump, fuel filter, alternator and so forth to let other people that would read my question no things that I'd already done to the vehicle. Oh I have also checked the inertia switch.

Spray a little starting fluid down the throttle body. It should run a few seconds on that. If so, it's a fuel problem. If it won't run on the starting fluid it's an ignition problem, no spark, or lack of compression. If you have spark and fuel but it still won't run it's time to do a compression test. If all cylinders test very low or zero it's jumped timing and you need to replace the timing chain and sprockets. Hope that helps! Jim