Power brakes dont really give you more braking energy per se they just require less pedal effort since your getting an assist & the downside is they give you less brake feel. I'm assuming you want more braking power. If your brake shop can arc linings I'd have them do it & take the drums in also. here it's $5 a corner & some ceramic shoes will help you even further as will a bed in (break in) procedure. If all that ain't enough then it's time for a disc conversion