[dsraven]

a few friends of mine have used rock auto. they found it to be quite a bit cheaper that local. you just need to ensure you order the right stuff because returning is like it will never happen. is your truck a first series or second series 55? they are different models. one is the early version, an advanced design and the other is the late version called task force. referred to by first and second series usually. post up some pics, we like to see what you have for a project.
I suggest to measure the drum size in diameter and width and count the number of wheel stud holes etc. then go online and see if they have what you need. I would also ensure that drums are the only thing you need. pull the lips back on the wheel cylinder boots to ensure there is no rust or leakage. check the hardware that holds the shoes down against the backing plates. check the backing plates for grooves where the shoes ride, a groove will allow the new shoes to slip into the groove and cause you issues. check the adjusters and return springs. check the park brake cables and entire system to ensure everything is free moving. check the axle seals to ensure they are not seeping. check the steel brake lines and rubber brake hoses. check the bleeder screws to ensure they are useable and not seized in. check the master cylinder for rust and seepage. check all the linkage from the pedal to the master cylinder to ensure it is not worn out or seized.