First thing you might consider is changing the gears in the differential. 3.55 or 3.73 will do you about right. Anymore and you won't happy pulling high RPM's at 55 mph. If you dont go supercharged, I recommend the Ford Racing GT 40 intake. You could also use a Ford Racing Cobra intake. A little cheaper and no EGR valve spacer required. If you want to go nuts building up the motor, I suggest getting a 5.0 from 87 to 92. (Like dude up above said.) MAKE SURE IT IS AN H.O. block. During those years they put extra nickel in the cylinder sleeves for added durability. They also came with forged pistoins during those years as well. Look through any Ford magazine out there. There so many combos you can go with you will get confused very quick. Even though it seems parts are cheap. It's gonna add up real fast. You gotta figure that Heads, Cam, Lifters, Roller Rockers, Intake and Headers are gonna be around$2,000 to $3,000. Then you have to upgrade fuel management ie. new injectors, larger throttle body, high volume fuel pump and regulator.
With 180,000 miles, you better redo the bottom end of the motor. And a set of new pistons. Good luck man, You DON"T have to do everything I listed above. But if you want the motor to survive the abuse you are gonna give it (and you know you will abuse it) Spend some money now or twice as much later. Good luck and let me know if you need some advice.