Shake Shake Shake

yellow rose said
If it's hitting on all 8 the crank is out of balance. Seen it many times.

As easy as it is to balance a crank, it can still get screwed up.

You may be on to something here. The engine has had this shake (at idle only) since I built it years ago. It actually runs killer, but just at idle I get that intermittent shake.

Dana67Dart said
To me it looks like a misfire, idling fine then a shake accompanied by a noise.

Look for spark in the dark.

No misfires. It hits on all eight and runs very smooth while I drive it. Crank my be the source of it.