As the 66 has a single chamber master cylinder (dangerous), I want to put a dual chamber on it with power assist, I am hoping it will be a good stop gap until I go to discs...when I do I will already have the master cylinder
Swapping out your single pot master cylinder for a dual chamber master cylinder is good insurance. I just bought a '67 master cylinder and bolted it right up. The hardest part of the job is flushing and bleeding the brake fluid.
cjponyparts.com has a brake line kit that will give you every piece you need except the 67 master cylinder to adapt the lines at the master. its like 17 dollars. as far the the power thing, you will need one of the conversion booster setups. this will cost more money. im just gonna do the dual chamber non-power setup for now, because when you think about it, its not really that hard to press the brake pedal and stop the car without power brakes.