I bought 535245 and it fit nicely with no modification. YMMV. I don't know if the bigger one will fit.

I've been very happy with the Wilwood 1" master on a stock booster with Wilwood brakes.

http://www.wilwood.com/MasterCylinders/MasterCylinderProd.aspx?itemno=260-8794

I was running the 15/16" until it failed. I couldn't find a rebuild kit for it so I switched to the Wilwood master. It requires a small amount of filing on the base of the master to get it to fit but once installed you can't see the modification and it looks very close to stock.

Here is a thread on hybrid Z about it...

http://forums.hybridz.org/index.php/topic/102754-a-one-inch-diameter-brake-master-cylinder-for-the-s30-z-cars/

Do you have to redo the plumbing on the 70-71 Z's?

When I changed the master cylinder I also added rear disks and a proportioning valve to the rear line directly after the master cylinder to balance the system. This required some minor plumbing changes. If you are just swapping master cylinders I don't think much if any new plumbing would be required.

Edited August 16, 201212 yr by steve91tt

There are two master cylinders for the 240Z, early and late. Early is $300 and late is $100.