1971 is outboard. Both of the mentioned parts are outboard.
817 is for manual brakes, 818 for power (disc) brakes. Both look identical, have the same piston diameter and reservoirs for disc brakes. But where is the difference?
From the Parts Catalog I need 818 (replaces orig part #3461176) for power disc brakes. Want to convert my brakes from manual drums to pdb. Already bought 817 long ago and wonder if I can use it for pdb.