Intel: I had a 93 F-150 with the 5.0 a few mods and 3.55 gears it ran well but I have driven a modded 4.6 F150 and it blows the 5.0s away.
I have some experience with the mods avaliable for F150s because I am a long time member of F150online.com forums
Here are the mods I think you should do:
1: The best and very first mod you should get (bang for the buck wise) is not exhaust or a K&N as many will tell you. However it would be some 3.73 gears this will make a VERY nice difference.
2: Now comes the exhaust. Get a good side exit setup like a Gibson. No need for dual 3" pipes or anything like that just a simple cat-back like the Gibson will do.
3: Now that you have better exhaust flow you need intake flow of course. Don't waste your money on a cold air intake or anything. I spent $200 on a K&N Cold air style kit for my 93 and it didn't do anything except make the truck sound cooler (this is going by track times not dyno numbers) unless you have ported heads and intake and things like that it's a waste. Just grab a simple K&N drop in element and that will give you all the extra air flow you will need with stock heads, intake and no forced induction stuff. You can get a K&N for like $40 at Autozone.
4: Good tires. Trucks usually have traction issues since there is very little weight over the rear tires. I used Pirelli Scorpion Zeros on my F150 and it made a night and day difference over the stock Firestones. Get some sticky tires and you will be suprised expecially if your truck is not equipped with T-Lok or limited slip.
5: Now this is where the deciding point is. If you now feel your truck is how you want it then I suggest having a performance chip programmed for it from superchips.com I bought their universal F150 5.0 chip for my 93 and it dropped around 2/10s off my track times. It should do even better on your truck because it has the computer controlled transmission so it will change your shift points to more performance oriented as well as increase line pressure to make the truck shift a little quicker and crisper. I paid $229 for my chip and it was worth every penny. On your model of truck though it could cost a little more because I believe you have to send off the computer to be reprogrammed with the new information. However if you plan to do more mods to your engine then skip the chip because you can't use N2O (Nitrous) or a Supercharger with the chip unless you have it reprogrammed.
This should get you a good start hope I was helpful. Let us know what you decide to do.
