Disc brakes traditionally have more drag then drum brakes. Back in the early 70s, some guys used to run the drum brakes with a loose adjustment on non-self adjusting brakes at the drag strip, in an effort to reduce brake drag. Exactly how much difference it actually makes would probably have to be subject to testing. The pursuit of the lowest ET had some guys doing some strange stuff over the years. The question is, how much are you willing to do for how much reduction in the ET? Gene