65' Cuda Drum to Disc advice

My son's '65 Cuda has the conversion to the 73-76 front discs; it works really well for general street use on that light early A-body. We installed a dual master cylinder from the same year range. (It was the 15/16" diameter bore MC, from a power brake car.)

If your rubber lines are old, replace them now. After 20 years or so, they will tend to deteriorate on the inner hose (where you cannot see it) and will often self-plug up when activated and hold the brakes ON.

New hard lines depends on the condition of the existing ones. Just inspect and make a judgement.

What size drums do you have in back? Depending on the rear drum size, you will need a proportioning valve to reduce rear line pressure under hard braking, to prevent the rears from locking prematurely. 10" rear drums reportedly can be made to work OK without one; if you go to 11" rear drums (like on a larger rear axle), then a proportioning valve, or proportioning with front pad selection, will be needed.