The wilwoods on my car are on a 9in spindle. My 14 inch ralleys would not fit. I ended up converting the whole car to big bolt pattern and switched to 15" billet specialties.
73 up spindles will increase your track width though. Id stick with the spindles you have and just get the wilwood kit. That is what is on the front of my Demon with a 340. It sees street and strip