new master cylinder or rebuild?

I dont know what the iron replacement your looking at looks like,,but the iron 67 and maybe thru 69 had a bolt holding the cap on the master if i remember correctly,,,

just because its old stock,doesnt meen its not goood,,,and get use to the made in china factor,,

i have a manual disc/drum combo on my 66, stock 1976 dart rotors/calipers 11 inch
and 11 x 2 1/4 or 2 1/2 drums, cant remember exactly,,,

i use to run the orignal 1976 iron MC.. til it crapped out,,,
then i switched to the mopar performance master,,,they had 2 choices at the time,,,15/16 bore, and i think 1 1/16 bore,,i thought i was having mc problems,,,and mopar doesnt carry the 15/16 any longer,,

i went to rock auto,,,you can cross refrence parts on that site and discover a ton of common items used on many different vehicles,,,

i discovered the 1988 dakota, manual disc/drum used a master measured in millimeters converted to inches is equal to 15/16 bore,,,it was half the price the mopar mc was when i bought it 15 years ago,,,,

i soon discovered it was not the mc i was having problems with ,,so i now have it as a spare,,,

the 15/16 bore stops my car as good as any power brake car i ever owned,,, 15/16 will push more pressure 1 1/32 will push more fluid,,you need PRESSURE to make a caliper work properly,,,and the 15/16 bore is easier on the leg to push,,,,for me its a win win,,,

i also have NO p/p valve,, i have super tall tires on the rear 33 inch tall,,and i use an adjustable valve on the rear,it take more stopping power to stop a larger dia tire then a stock tire,,after market p/p valves are much better design then an orignal type , the choice is yours,,,, your local auto parts store car hook you up,,,get a new one not reman,,,,,unless you get a life time warranty and keep your paper work,,,,