I just finished the conversion recently on my '54. You'll need two of these for the right side..... H2515 You'll also need two of these for the left side..... H2514 And, you'll need two of these hardware kits for all 4 brakes...... H7045 O'reillys has them too.
You didn’t say so I’m ***uming your doing rears. I remember problems with fronts when the factory did them and I understand if you are installing front discs why you want them in the rear.