i know those master cylinders can run a set of 2 piston cals but i dont think 4. id be going with the bigger 280z master cylinder. im doing brake work myself so ive been doing a little research too. also with the fittings i would be willing to bet theyre not the same but its not hard to find adapters for them. also what version of the 300zx cylinder do you have, a z31 or z32? come to think of it a cylinder of the 350z would for sure run those cals. good luck hope i was of a little help.