new master cylinder or rebuild?

the aluminum units only use a 2 bolt system,,,your orignal iron bolts on using 4 bolts,,,you will have to buy the 4 bolt to 2 bolt adapter, from a moparperformance dealer,, or maybe summit ?? or jegs??? macini has them,,

the question isnt will one from an M body work,,the question is,will it work properly,,or as well???
your car ,,,,4 drum ??? or disc /drum ??? manual or power ???? i have disc/drum,manual and i use an aluminum 2 bolt master 15/16 bore from a 1988 manual disc/drum dakota,,,,

the bigger the bore the harder it is to push the pedal,,,,your combo will decide what master you need,,,,do a search on rock auto .com