If you have a later model engine with old style separate coil ignition I think you will have to do some experimentation. You could start with some measurements from spark plug to distributor hole and write those measurements down. Then check a stock set of wires for your vehicle at the parts store and see if the wire lengths will meet your need. Make sure you allow enough extra length to the wire measurements to allow for a nice set of wire looms to keep the wires away from the exhaust manifold and engine block.
I would use a long piece of romex cable (house wiring) to estimate the length, because it will bend an hold its shape while you figure out how long it should be. Once you are in the parts store you can lay out the wires and see if there are enough of the right length to do the job. Just go to
www.napaonline.com and enter your vehicle information to get started.