Lowmoin
I suggest you follow chris's adive on the search and im sure you will come across the sigma conversion. I'm not sure if could use the rear. I have a h165 in the back of mine and im happy with drums on the rear. You could always put a h165 with bluebird disc rear end.

Wurzel
As I mentioned above Im running a drum rear end and its fine. The handbrake works a treat. I have a pic of the linkage that was modded if you you want me to post it up. You need to get rid of that valve and then you might find you can adjust it up alot more. What master are you running?
I would start to look at a full setup on bluebirds and see what different on your car.

Chris
Keep me posted, measurements before and after is exactly what im after. thanks

click here for maddat kit and scroll down