When you put a dual res on, you split the fronts and rears and double fluid flow. Also, instead of a 1 1/4" master controlling all four corners through one line, you have 1" master going to the front and a 1" master going to the back on the dual set up giving you more braking power to each corner. My set-up works great and I put the 1970 C10 (or C20) master/booster drum/drum set up on all my builds.
Who's the PO of the bus??? 6 miles which way from CP???
Scott