Here's your choices using OEM parts and no machine work:

1967-1968 spindles, rotors, calipers, master cylinder and associated hardware and plumbing. That set up uses 4 piston calipers and 2 piece hub/rotor.

1969-1970 spindles, rotors, caliper, master cylinder and associated hardware and plumbing. That set up uses single piston calipers that are more reliable and much cheaper, but new rotors are very hard to find and very expensive when you do.

C3 Corvette, the spindles interchange but you must use the Impala steering arms. You'll also need the Corvette hubs. Rotors are cheap and the 4 piston calipers are readily available. Look into the ones that are sleeved with stainless steel. Since you'll still have drums on the back, use an Impala disk brake master cylinder.

I'm doing the Corvette conversion on my '65 SS. I'd avoid some of the after market kits that use the stock drum brake spindles and 11" A body rotors,calipers. The OEM options give you a larger 11.75" rotor and don't move the front tire track width out. By the way, I think you'll need 15" wheels to clear the OEM disk brake options.

Bob

Bob