are you looking to use a stock 73-up style disc brake set up?? if so they are probably heavier then the drums.. if you go with something like a wilwood set up they may save some weight....
give bill at reilly motorsports a call.. he can help you out either way you decide to go....
Phone - 570-443-7440
Address is:
Reilly MotorSports, Inc.
2323 White Haven Rd.
White Haven, PA. 18661