Pn# - BLK103LMK - 1pc Ea 66 GM-A body Chevelle, Lemans GTO, Cutlass 442, Skylark GS, Dual Master Cylinder conversion with Master cylinder, brake lines and block. Standard 1 bore for manual or power Front Drum brakes. This is for all 66 with drum brakes converting to dual master cylinder from the single master cylinder. Not for 64-65 they have a 3/16 front to rear brake line. This is the master cylinder used on all dual system conversions - it breaks the front and the rear up and separates the one system into two.
It fits right in place of the old master and bolts right up. It has the hard to find correct 1" bore for drum brake cars - the later 1 1/8" master will not work the pedal will be too hard to push in.