The brakes are a bad design. Most drum brakes dont stay properly adjusted for more than a few months. Even tractor trailers with "automatic slack adjusters" will be out of adjustment when the drums get hot. DOT has a field day siteing trucks for mis adjusted brakes. The E brake setup is even worse and prone to the levers rusting up at the piviot point preventing them at first from releasing correctly, thus dragging the brake, then fom being engaged at all. There is also no where near enough levrage on the handle even when they are working correctly, it requires a shoulder poping yank to get the e brake to engage due the the poor leverage. I have recently replaced the entire E brake cable and I end up servicing (taking apart, soaking the levers and removing the rust) every time I inspect the truck in the summer. I just hate them. Disc are so much easier to maintain and work so much better. I did not expect such a big differance but when I converted my Mustang to rear disc I was amazed at the extra and evenly applied stopping power, The E brake is also self adjusting (in the calipers) and works all the time every time, just as well down hill as up. Drum brakes are "self energising" in one direction only and tend to slip more backwards.
I do like the 4 piston front brakes, good power there but mine have been prone to jam when you try to push them back in for brake replacement even when the dust boots are intact. Its almost better to remove the dust boots and clean the pistons than risk jaming or blowing the seals by trying to push them back in. With a 4 piston caliper and two calipers, this turns a 1.5 hour brake job into an all day event. Its faster just to run out and get a new caliper and replace it if one jambs up on you.
Also, since I did put rear disc on my 5.0 my front brakes wear half as fast since the rear now work. The car handles WAY better on the binders now. The only concern is the posibility of needing a prop valve but I have found in most cases the volume it takes to work stock size rear disc is about the same or less that what it takes to push the drums often dialing in a bit of rear trail brak bias wich is good since it allows the front to lock up well after the rear so you can still stear under hard braking. Ony concern is with this pickup with a soft long travel suspension and being so light in the back that it will get so skidish, testing will tell if a prop valve is in order or not.
I hate durms, I hate these drums even more.