That is the same kit that I used in my 64 GT and I did not use a proportioning valve. It worked great, with zero issues without valve. And my 14" Cragars fit fine, with the 5x4 rotors.Yes, I’d like to keep the 5x4 rather than drop more cash on new wheels and tires too. This is the one I was thinking of getting. Comes with lower ball joints.
DBK6272A-40-B - 1962-1972 Mopar A Body Small Bolt Pattern Standard Disc Brake Conversion Kit w/ Powder Coated Black Calipers