My Super Six is hitting on all eig....six

Adjusted Chevys that way with my dad when I was a kid. Tried it on a running V8 440 with no success but as mentioned earlier you can idle a slanty down real low to do it. Another thing he taught me with the Chevy was he adjusted down until the motor had a slight skip then backed off and readjusted. He said it removed build up that was sitting in the lifters. Sometimes people would have to readjust a few days later if they didn't do it.