Get in touch with someone like Day motorsports. That set up you have is the typical IMCA Modified set up....
Granada rotors, pinto spindles with the brackets to accept the large GM caliper. Wilwood does have a caliper to fit those brackets yes...this link should take you to the right ones...
http://www.daymotorsports.com/produc...BRAKE-CALIPERS
Hope this helps. Im running the same set up on my Cobra as well. Just a hint...Just about any auto parts house sells all the parts except the brackets to set that up.