$cyl to V8 swap

rearend, fuel and brake lines, suspension (you can still use 4cyl springs, it'll make your car sit lower and the weight transfer is just as good as v8 springs if not better), engine, engine harness and tranny (apparently), computer, rack and pinion, break booster and master cylinder, gauge cluster, crossmember, rotors, calipers and spindles. i recommend using the dash harness out of your GT too that way you KNOW it will all match up. Just pull the dash cover off then pull the harness out still connected to the metal dash frame. I know this all sounds really confusing and overwhelming but it's really not. Just gotta get in there and do it and you'll see it's all just nuts and bolts. there are a few other things i can't think of off the top of my head but those are the main/major things you'll have to change.

i converted a coupe to a v8 a few years back. when i first started i had never done anything of that caliber before but it's fairly easy...just time consuming. when you get to changing the front suspension and brakes, a shortcut i did was instead of taking each individual component off and putting them back on the 4cyl car, remove the entire setup in one piece by disconnecting it at the a-arms and top of the strut. that way the strut, a-arm, rotors, spindles and everything are already together and you just have to bolt them back on at the 2 a-arm bolts on each side and the top of the strut to the strut tower. then just put the v8 calipers on.

here's a link to a recent thread about this, he's going carbed though.... http://forums.stangnet.com/showthread.php?t=681833