20" I just bought new ones this afternoon and according to the book both front and rear is 20" (but I got 22" for the rear) The front will take 22' or so. The rear will take 25" I think
I removed an 18" blade assy from a wreck & the arm had NISSAN embossed into it. Don't know if it is an OEM item for the Z32 though.
Well, the blade is separate to the arm. You can put any length blade on the arm and you can buy the blade with new rubber for less than $10. It is also easier to replace the whole blade assy than just changing the rubber so I doubt there would be many original blade assemblies left.
