this information may be helpful to anybody doing a disc conversion. 11 inch 70-78 camaro rotor the measurement from the outer bearing to the rear of the rotor seal is 3.6 inches. from the front face of the outer bearing to the rear of the inner bearing 3.4 inches. using A2 outer bearings and A6 inner. A2 dimensions .750 id x 1.781 od x .656 wide. A6 dimensions 1.25 inches id x 2.328 od x .625 wide. if your spindle is .750 outer and 1.25 inner its a fit ,you may need a spacer for the seal to ride on. if the inner bearing surface on the spindle is 1.375,use the A13 bearing. make some brackets or buy them for your application. calipers, use the d52 with d52 brake pads. you can use d614 pads for more stopping power. you will need 15 inch wheels made for disc brakes.
in my case i needed the A13 inner bearing and A2 outer. i need a .500 wide spacer for the seal to run on. the factory 57 bearings have a race that with some narrowing will serve as the spacer. a 64- 67 gto spindle may be the same as the 57 pontiac in dimensions.