If you're looking to help your bud stick with drum/drum but update that master cylinder to dual for safety reasons, check out this thread by ChiefRocka
http://67-72chevytrucks.com/vboard/s...ht=brake+lines
"a NEW drum/drum master I picked up at Kragens for under $30...I asked for a 67-70 IMPALA drum/drum car...non Power Booster....Can't beat the price !!!"