bouncing timing mark

Mad Dart, that device from Hughes will stop the slop where the distributor shaft meets the intermediate shaft/gear but it does nothing to keep the intermediate shaft/gear in place. The distributor bearing/bushing (inside the distributor housing) has to take all of that. The fix that Dvorak came up with eliminates that. It uses the distributor housing (with a bearing between the housing and the stabilizer) to secure everything. It's just a better way to go and it solves both problems. I still reccommend the timing chain tensioner regardless of what's going on at the other end of the cam.

From Dan's site:
Timing Stabilizer - A devise that installs between the body of the distributor and the intermediate shaft "Tightly." Eliminates timing fluctuation by keeping a constant pressure on the intermediate shaft which in turn keeps the cam from moving, which keeps the CAM from "sensing" cam in and out movement, I-shaft up and down movement and relief spring cycles from the oil pump. Final fitting required. $79.95