Vibrations and pulsations from having a 4 5/8" stroke are 2 different things. The Fisher and other stuff out there do work on vibrations, but really there is not much you can do with the pulsations from that long stroke, short in counterbalancing like the Twin Cam B engine. Years ago I put an S&S 4 1/2" stroke kit in a 1200 shovelhead I had. Ran great, but nothing worked to get rid of the pulsations. Now, there are some beefier aftermarket frames that seem to help. To be honest, I never rode a solid mount bike with an extended stroke that really was smooth. When I built my custom, I went with a Kenny Boyce Pro street rubber mount frame for my S&S 96 incher. Anything above idle is smooth as glass. Maybe I'm getting old (hell, I know I am) but I prefer rubber mounts on anything I ride anymore.