I am in the process of converting my 65 GMC Single MC to a dual MC. I will be using a 68 GMC dual MC because it mounts perfectly. I have been reading through the forums and still have a few questions. I plan on leaving the four wheel drums due to the fact that i will be driving the truck less than 2K miles a year. In some forums people recommend a proportioning valve and in others some recommend a distribution block. What is the best way to go for my setup? And what is the difference between the two? Thanks for any information.