Brake replacement

Hello to everybody!

I am in need of advice regarding drum brakes to disc conversion. This Dart has two different tires, size 14 in the front and 15 in the rear. I read in one of the brake vendor's site, that some disc brakes conversions, may not work for some models with 14 tires.

Looking for something similar to this:
1966-74 Dodge Dart Mopar A-Body Front Disc Brake Conversion Kit for 5x4 Bolt Pattern & Manual Brakes

The master cylinder is also leaking, I made/installed an extra gasket, bent the wire holder with a pair of pliers and still leaks a little. When driving the car and applying the brakes.

Thank you for your help and advice.

Pictures of the front and rear brakes in the car:

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