Front disks became standard equipment on January 1, 1976. So, nothing after that would have SBP drums, it was a federal mandate. I said '75 earlier, but it was '76.
But from '73+ even all 318 A-bodies had standard disk brakes. /6's were the only ones that could have drums, and even /6 cars with sure grips added got disks. From hamtramck-historical,
