Datsun 120y brake Master cylinder upgrade

[120y_fj]

Whats a common upgrade for a break master cylinder?

can make up adaptors from booster to cylinder

but need something that is thin because i dont have much space from intake manifold and brake cylinder

[Bartman]

Late 120y's had a booster.
There should be a few datsun cylinders that will fit. But if you need a shorter one, you may have to talk to a brake shop?

[Datto_610]

The 120Y boosters are the same as 610 180B IIRC, so you could use 15/16 from a 280zx or a 7/8 from 720, and I think 330 cedrics run a 7/8 as well. All depends on what front brakes you plan on running, but those M/C won't be any different in size physically to what you already have. So you might have to look at adapting something from another make or model.