Brake question

Just bought a 68 Cuda, and would like to swap to disc brakes... What reading some posts there kits and other swaps.. I found a 75 Dusted today with disc brakes would they fit my 68? and what would I need off of it..

Yep, I would get the upper arms, spindles, rotors, calipers, proportion valve, fluid lines everything brake related that I could get, especially if its a recently parked donor with a brake fluid system that is still closed.
The upper ball joints are different but... if the upper arms in the junkyard are bent, you can buy adapters to fit yours, smaller ball joints to the larger hole in the disc brake spindle.
If I discover the calipers, proportion valve, master cylinder, whatever, from the junkyard was also junk...That's how it goes.
If this donor has the lower arms with tabs and the stabilizer bar, those won't work with your K member but you might sell those to someone here.
If the donor has all that and a good V8 K member, you could gain that stabilizer bar and failsafe motor mounts along with disc brakes ( swap in the K member and all ). It snowed balled a bit didn't it?

What Redfish said, +
Disk Brake Conversion Info

Some other thoughts.........consider swapping the calipers side for side which gives more room up front for antiroll/ sway bar. This requires (I think) Volare hoses

I don't have the part no. but there is a later / larger bore caliper which will give more braking force with same size master. This of course will change front/ rear brake ratio, but you might need a prop valve anyway

Consider getting the K member which will have spool mounts, depending on what engine/ /6 vs 8, etc.......

Check out what you have for steering linkage........the steering boxes have two different pinion shaft sizes over the years. These must mach the steering arm, and the steering arm must match the early vs late linkage

in other words the Idler arm, pinion steering arm/ steering box shaft size must all match, and those much match the center link according to 72/ earlier vs 73/ later

All of this with the linkage is INDEPENDENT of drum/ disc brakes