This document is based on a "ALFA Romeo Association tech session / presented by Larry Dickman Jr., ALFA parts Exchange" paper. Mike Nakamura Larry's Guide a Montreal 1971 update and I my 1972 Montreal used the information from Mike upgrade. I've added the information of Mike, a little more clarity and detail.

Larry developed this upgrade in common 14 ALFA wheels fit and there's a multiple routes can follow in order to achieve the final result. You can change old 115 rotors iron to create hats and you add new rotors, or you can edit custom aluminum hats.