Running just rear brakes, one can get away with braided because the length is short , on F/C and Altereds there must be Heat shield covers over the exposed line. Running braided to the front inside the frame can be damaged by fire or welding repairs if one is not carefull.
Old theory is that if too much braided is used that the brakes get spongy because pressure expands the nylon, Thats true, but we dont rely on the brakes as much as a road race car to go fast , we just push or pull a little harder.
Running steel/SS lines to the front is cheaper and lighter then going braided
