I'm not familiar with that particular kit, but it should make a big improvement in stopping. I'm doing a disc brake swap on my 65 Barracuda also when I tear it apart to redo it. I'm swapping to big bolt pattern all the way around, so I'm just using a front disc brake system from a 73 and up A body.
Just ordered a complete kit for my 65 valiant, remake of the Kelsey Hayes four piston factory type brakes from SSBC- USA .
uses both bolt patterns on rotors and goes on the stock 10 " drum spindles.
Will update when they get here.
Lon
This is essentially stock style disc brakes for the car. The Kelsey-Hayes style 4 piston calipers used on the Mopar A-bodies and Mustangs of the era. Works well.
Bonus is that you can retain the 4" bolt circle wheels if you prefer.
If you want a higher performance level and are willing to go larger diameter wheels my favorite options are from "Dr Diff". Best for you to call him if you have questions. His "Stage 1" kit is same as stock '73-'76 disc brakes, not better than the Kelsey-Hayes style in my opinion. Each level has an increase in cost and minimum wheel size. Brakes :: Kits and Assemblies
Disclaimer: I have a variation of his "Stage 4" kit. Which, including master, 2 piece Baer rotors, calipers and etc would set you back about $2k. I have 18" wheels...