Ticking 340

My 68 Dart had a lifter tick. I replaced the rockers, rocker shafts, push rods and lifters and still a tick from more than 1 cylinder. The motor runs fine and I didn't see any major wear on the cam but it still ticks. Is it the cam? What's left? I put 39 weight oil in but it didn't help. Any help would be greatly appreciated.