check out or call one of the brake vendors for verification.

(http://www.ecihotrodbrakes.com/brake_facts.html)
(http://www.inlinetube.com/) Inline tubing

"The smaller the tube, the more pressure it creates and the better the brake system will work. Disc brakes require about 1000 lbs of pressure and drums about 300 lbs pounds. Disc brake cars use 3/16” tubing and drum brake cars use ¼” tubing. If you are building a street rod that has front discs, the entire system is typically plumbed in 3/16” tube." (Call Inline tube for technical assistance)

http://www.inlinetube.com/"