Geoffrey Hacker

Hello All...This is my first post - I hope it shows ok. I have a 1975 Olds Delta 88 convertible. It has all options except power windows. I would like to convert to power windows but would like advice from someone who has done this before. Does anyone know if the wiring loom is already in place under the dash? Or...will I have to find an "underdash loom" and connect up to a power source - and each of the 4 windows too. Thanks for any help you can lend. My e-mail is geoffrey@grhacker.com