Hey Captain. . . Thanks for that. . . I have read several iterations of the nut removal and tried to imagine the force it would take to push that staked portion away with just brute force.  Nice to have a better way based on real world execution. Dug out my 1 hp dremel today. Thanks again. . . 

I don't want to discount other methods but if you have the room to hammer and a properly shaped cold chisel you can spread that staked portion out again, only affecting the already missing portion of the threads.  The farther you spread it the less leverage it has on the threads.

Here's a source for rebuilt racks..  They also have new ones for the 280s.

https://www.buyautoparts.com/buynow/1971/Nissan/240Z/Rack_and_Pinion/80-70090_R

9 hours ago, Zed Head said:

I don't want to discount other methods but if you have the room to hammer and a properly shaped cold chisel you can spread that staked portion out again, only affecting the already missing portion of the threads.  The farther you spread it the less leverage it has on the threads.

This really is the best way although it is more work, even with cutting off the staked portion of the nut with a Dremel some damage to the last couple of threads on the stud axle is inevitable.