Your truck should have a Hydrovac booster mounted on the frame. It is a large canister with vacuum and brake lines going to it. If memory serves me they add about 900 psi to your stopping pressure.
If you decide to put a modern dual pot master cylinder on your truck in place of the original, make sure the master cylinder bores are the same size.
My trucks all have the stock systems and do just fine, but they are also 100% new parts, including the lines and hoses.
Mike B
