If the new pro-cap doesn't work on your application, these MSD cap-a-dapt will do the trick. The MSD cap-a-dapt adapts a large, Ford style cap onto your MSD distributor. The rotor is injection molded out of Rynite?.
Red Fixed Rotor #8445 & 8423 MSD Race Billet Distributor STREET DRAG 100611-4
Black Fixed Rotor #8445 & 8423 MSD Race Billet Distributor STREET DRAG 071015-9
MSD 8567 Distributor Rotor, Brass Terminal, Crab Cap
MSD 5501 Cap & Rotor Kit for Street Fire/GM HEI Style Distributors
MSD 8421 Adjustable Rotor Assembly
MSD 8470 GM Rotor "E" for 8473 & 8485 Distributors