Just to add a little extra, Front Disc Brakes can also be used from other '67 to '70 Full Size Chevy cars (Impala, Caprice, Bel-Air, Biscayne). Although the '67 and '68 are Dual Piston Caliper set-ups, and are not that desirable to use. The best ones are the Single Piston set-ups found on '69 and '70's, although not all '69 and '70's had Disc Brakes.
They are pretty hard to find and whenever I get in a set, they sure sell pretty quick.
An additional note though, when using these parts, you will also need to switch to 15 Inch Wheels.
-Parting Out over 75 '58 to '73 Full Size Chevy Cars-
-National Impala Association
-Vintage Chevrolet Club of America