I would check the inner bore size and replace it with one of the same size, if your happy with the old one If you want more stopping with less pedal pressure, make the new one have a smaller bore size by 1/16 to 1/8 or so Years ago I made the mistake of buying a master cylinder with a bigger bore size than I took off on a race car with a old iron dual master cylinder because I was racing the car at the Winternationals and in a hurry to get it fixed for the next day The parts store didn't have the direct replacement one but they had both the next size smaller and bigger. I picked the bigger one, bigger is always better , right? Wrong on hydraulics cylinders and pressures I really had to use a lot of pedal pressure to get that rascal to stop at the end after the change