If you go disc you really should go with Power Disc which means you really need an offset bracket. You are into changing spindles and such if you do this right and you certainly do not want the 67-69 hard to find and expensive set up. You would want 70-72 or go with the late model set up. You really just start to lose originality. Frankly even if they work those GM booster folks use just ruin the look of a hemi engine bay in my opinion. I believe drums set up is actually lighter also. Your maintenance work is easier with the manual drum set up. Just get a new equivalent MC.