I dont know how flat it is where you live, but most of these vehicles were built to travel slowly by modern expectations, and are probably more "under braked" than "underpowered" Repowering is probably relatively easy compared with upgrading the brakes. In most cases the best one can hope for, is to have the brakes in top original condition. Keep this in mind when you fit the 7.3 litre v8 diesel in your HUP.
(What is a CSB?)