My `69 Hemi roadrunner has factory manual disc brakes. Paul
that was NOT a factory OPTION - all '69 b-bodies with disc brakes were fixed 4-piston calipers with a Bendix dual diaphragm power brake booster
Then explain why manual disc brakes are listed in the parts book
You have to look at vehicle. That was A body only. KH system.
Look at R and W and it is not an option. Look at Hemi engine and Power disc only.
Someone harvested and expensive booster and hemi linkage. Or got tired of moving MC to take off valve cover and switched to manual MC. I don't think you car is a good braking with those bendix in front, but for a show car/ occasional cruiser no problem. Do you have B51 on fender tag?