I'd definately agree with the adjustable bias box - and using the 164 front brakes on the rear as well - although it might be worth looking at how the handbrake caliper is fitted so it could be transferred.
Hydraulic handbrakes are now available on production cars, so the original construction & use regulations (which stipulated cable operation etc.) have been amended. A £150 hydraulic handbrake assembly from Demon Tweeks (complete handbrake, mechanism and hydraulic master cylinder) should do the job fine.
I am using the 'Sud inboard front brakes (with handbrake) at the back of the Green Machine, with Ford M16 (made by ATE
) calipers on the front and AP Racing master cylinders with a bias bar. I set up my brake balance by starting with the bias on full-front and doing a series of sharp brake applications on a conveniently wet road. I progressively wound back the bias until the front wheels just locked in advance of the rears. The wet road helped to keep the speeds down to safe levels although probably has some small effect on overall bias (less weight transfer at slow speeds). Nevertheless, the first time I floored the pedal at speed (decelerating off the motorway for a sharp exit road from 70+ mph) the result was very satisfactory, even without servo assistance (go for the smallest m/c bore size if you do away with the brake servo).
My pedal box is the original '78 Alfasud unit welded into the chassis. There is enough room for a pair of AP Racing master cylinders (with remote reservoirs) where the single tandem cylinder was fitted, and the original clutch cylinder stays in the same position. My brake pedal has been modified to incorporate the sleeve for the balance bar spherical joint, and I've even been able to keep the natty little shield-shaped rubbers!
Are those pictures of the one-and-only Sprint 6C? The rear louvre looks different from the factory photos somehow... perhaps because its colour-coded? Still haven't seen a picture of the engine/transaxle combination on the Alfa either...
What is that just behind the car in the rear quarter view? Clearly a GTV, it looks like it has a "periscopa" dorsal air intake on its roof - GTV6 mid-mount, perhaps?
Good luck, Sixnut, you'll need lots of enthusiasm to see it through, but I'm really looking forward to seeing the end result!