Currently has the J50 power drum brakes. Is the master cylinder, booster & p valve the same as what was used on the JL2 front disc brake option ? I do have a complete setup from a 72 monte carlo but if I can use any existing already mounted parts it would save some time and possible headaches as I know my parts are functional.

Thanks,

nope, gotta have it all

spindles, shields, p valves, booster, master cylinder ect...

also check wheel bearings, some had 1 piece rotor/hub assemblies and some had 2 pieces

if they need replacing you can get slotted rotors which may or may not add to braking for the same price as stock replacements

oh and on that master cylinder, save the headache and buy a new one...very cheap part

get ready for a lot of bleeding too :D