Top 2 are from an original 280Z with R200
Half shaft off a 240Z has narrower neck, while one off a 280Z with R200 has a thick neck.
When 240Z owner upgrade R180 rear differential to R200 differential, most cars have a problem with LH side(Driver’s side for US) half shaft u-joint durability once the car is lowered.
It bottoms up when the car hits a bump. Since R200 case is bigger on LH side, the half shaft length becomes too long.
Many people modify and install CV joint type half shaft from 300ZX, though it is not an easy task.
Now some 280Z cars come with R200, and I would like to see if they had somewhat different half shaft from Manufacture.
I pulled a set of half shaft out of an original 280Z car with 5 speed & R200. And then compare them with ones off a 240Z.
They measure the same both shortened and stretched. Yet I can see some difference here.
First of all, the casting # is different. And the shaft of the neck near welding seam near U-joint is in different shape.
I can see Nissan tried to build stronger half shaft for more torque.