Conversion kit updates 1973-1982 FX FL models from a 10 disc to an 11-1/2 disc. This kit includes a 11.5 drilled brake disc in stainless steel mount bolts and the dual aluminum anodized piston caliper. By converting to this style caliper rattle and chatter will be eliminated and a much greater stopping power will be achieved. Use with 5/8 bore master cylinder. 1973-1984 FL 1973-1984 FX