Need A Good Master Cylinder

For manual brakes, you surely want the 15/16"D bore, which raises the DoctorDiff price to $125. On my 64 Valiant I used a 2-4 bolt adapter plate ($30 ebay) w/ a 95-99 Breeze ABS alum MC ($25 ebay). Its 7/8" bore gives an even easier pedal. I used the same MC on my 65 Dart and 65 Newport, which both have boosters. Has standard 3/16" inverted flare ports, but your tube nuts are probably a different size (69 Dart used different F & R nuts?). Might also be true w/ DrDiff MC, which I think is same as 1980's Dodge trucks. You might need a double flare tube to remake your tube ends. If you haven't been doing so, flush thru new brake fluid every ~4 yrs in all your cars, or use DOT 5 silicone fluid. SoCal guys might go 10 yrs between flushes.