a-body rear end help

thanks guys , this is helpfull. i was planing on selling the car but the more i look and drive it the more i like it and i know i wont find anougher one as clean and rust free as this one. this is a number matching all orginal minus wheels , intake and carb ( i have orginal wheels ,intake and carb put up ) no metal work have been done to car. will i hurt the value of car if i do the up grade on rearend and front brakes ?