I must say that these trucks were not built with braking systems strong enough or reliable enough for 70 mph driving on the freeway.
Properly rebuilt, the stock brakes are plenty adequate for Highway use. Now, I don't have anything against changing to disks or dual circuit master cylinders, but the stock brakes are much better than most folks give them credit for. Changing to disk brakes is not a "have to" in order to run highwya speeds. I run those speeds (and sometimes faster) regularly with stock manual drums
