For what it's worth, I upgraded my '66 Valiant (SBP with 14" rims) to discs about 2 years ago, and I used the Scarebird kit.
I'm very happy with the results - I've had zero problems and I highly recommend the Scarebird kit.

Hello,
I wanted to weigh in on the conversation. I did the scarebird conversion maybe 5 years ago. Have put alot of miles on the car since and have been very happy with the performance.pro/ con as i see it:
Pro; 1) works way better than stock 9in drums.
2) low cost installation
3) parts available at most auto parts stores
4) ease of install, may or may not be a concern

Cons; 1) i am now sort of "Stuck" with small bolt pattern in front, and my plans for the car have changed.
2) wheel selection is a bit limited by the sbp.
3) rear axle getting changed out to a beefier unit, therefore requiring carrying 2 spare tires to cover a flat tire.

To summerize, i am happy with the scarebird install, however had i know about future mods, i may have gone big set -up in front all at once.
Cost not withstanding.