I'm not clear on what the custom SS brake line will fit. Will they be a direct fit hose for a 71 bronco getting an EB D44 with 78 D44 disk brakes?

These hoses are designed to allow you to use 76-79 Ford front disc brakes on a 71-75 Ford Dana 44 front end without any hose adapters. The caliper ends are just like the 76-77 stock Ford Bronco disc brake caliper hose. The other end is the custom part. It fits the 3/16 inverted flare hard line which is stock on 71-75 Bronco Dana 44s.