It might seem like a daunting task, but changing plug wires is really very simple. They might be snaking all over (or under) the engine, but each wire must run to its specific place on the distributor cap. Changing them is easy if you do three important things before taking anything off. These procedures will ensure you will never scramble the wiring.
Your owner's manual or shop manual will tell you which cylinder is #1, so refer to it. Many engines also have the cylinder numbers stamped on the intake manifold as well, and a quick look will confirm things. The reason it is so important is that #1 cylinder is the one to which the entire engine is mechanically and electrically timed.
Once you've found #1, pull its spark plug wire and carefully unwind it free up to the distributor cap. Before removing it from the cap (it just pulls off) make a chalk or "white-out" mark on its position.
You need to know which way the distributor rotates inside, either clockwise or counterclockwise. The easiest way to find the direction is to lift off the cap and crank the starter a few revolutions and watch. You might find that information in the shop manual or tune-up portion of the owners' manual. That's all you need to do.
Now you need to find the firing order. Look at your intake manifold again, because it's probably stamped on the manifold. If not, look in the shop manual or owners' manual. Also, determine for sure how the cylinders are numbered. Most V8 engines have 1-2-3-4 on one side and 5-6-7-8 on the other, but make certain which cylinder is which.
Once you've found #1 on the cap, put its new wire on and dress it down to the sparkplug. Follow the firing order to get the next one (let's say # 5, for instance) and put that wire on the next position on the cap in the proper direction of rotation, and so on...
As each wire is placed on the cap, thread it around the engine to its respective spark plug. Then go to the next wire and continue that way until all are placed correctly. It will start and run perfectly, we promise.