The dampers are different between the cast crank and forged crank motors, and cannot be interchanged, on the V-8 engines. The BB forged crank damper will work on a slant six, but the pulleys will not be aligned. This is not a problem on a race motor, but causes clearence problems on an "early" A-body street car. There is no difference in the dampers for the cast crank and forged crank slant six. Only the location of the timing mark.