the "huge" brakes (as you call them) will fit on those spindles (in the picture)as they are the same dimensionally as the '73-'74 challenger spindle. HOWEVER... the upper A arms ARE different from the small bolt A-body cars compared to the large-bolt pattern A-body cars with disc. The large bolt, latter cars used a LARGER upper ball joint that must be used with the associated spindle. Believe it or not, that spindle in the picture can be used on a 70-74 e-body OR a 62-72 B-body.
Here is a web site with some quality set ups for brakes:
www.arengineering.com
