Hy mechanic58, my jobber parts books show the rear wheel cylinders as United part number 3677, that crosses to Napa p/n UP3677 reserve online price $52.49, the Raybestos p/n at RockAuto is WC3677 $61.79, hope that helps.
Hmm, thanks for that information. Looking at the picture of it on RockAuto though it doesn't look long enough. I still haven't finished getting mine apart yet. Once I do then I'll be able to figure this out more definitively.