When I bought my 55 12 yrs. ago it had the stock spindle manual dual master 11" rotor rear mount metric caliper conversion installed. It has served me well over the past 70000 miles but I am considering an economical upgrade. Can I simply change the brackets and use the larger GM calipers on my rotors? If I do will the larger pistons require a master cylinder change? I also plan on upgrading to steel braided brake hoses front and rear for a firmer pedal.