all of the rwd trx bluebird rear discs are the same

and D he is using the alloy bluebird backing plate and modifying that to suit the 1000 drum bolt patten

oh and just a little bit of info, r31 rear discs go onto a h165 pretty easily, so if h165 discs go on the front of a 1000 easy enough then you would think that r31 rears would also be able to be adapted pretty easily. and you can fit 13s over them piss easily and replace the handbrake caliper with one from a commodore to simplify it a bit
probably a bit more common then trx bluebirds