I searched and havent found this so i thought I'd share. Hopefully this helps the skyline community. I found parts to rebuild the rear propeller shaft cv's for an r32 GTR. ( likely to fit some other models) the joint itself is nearly identical to a "930 cv joint" which fits a 930 turbo porsche. The joint, boot, and rear grease cap are made by a company called EMPI which makes VW accessories etc. The joints can be sourced elsewhere as well.
The boot, inner race and bearings are identical to the gtr joint and the outer race and grease cap are very close. To use the entire joint and cap you will need longer bolts and to grind the grease cap flange off.
With more research there may be a joint available with the correct width but will likely need the cap modified or the outer race machined to fit exactly as oem
Part numbers below
Joint porsche # 93033203400
Empi boot # 86-2515
empi cap # 87-5870
i rebuilt mine. Hopefully this helps someone.
