Shake Shake Shake

I've concluded, thanks to everyone's help here, that there are a few contributors at play here.

Detroit Iron said:

It's intermittent and and cyclical.

Click to expand...

Yep that shows in your video. Been trying to think of things that run at different rotational speeds and that could phase together at times (shake) and then out of phase (no-shake). Things like fan blades that are at different speeds than the engine, or something in the trannie, or something that is precessing around like maybe those PP weights, or a shaking effect in the carb.

Just one more long shot: Put a voltmeter on the battery when idling and see if the voltage is steady or is varying up and down with the shake coming and going.

Does it seem any different than this engine?

he says little cam;
but it peaks at about 5550 with log manifolds, and idles at 800plus at low vacuum.
I guess it depends on your definition of small cam.
Ima thinking 284ish advertised, maybe a tad either way, depending on the manufacturer. That's about two cam-sizes bigger than the 268/276 that came stock.
And I didn't hear the cyclical

My Commando 273 does the same thing. I will start looking at all the ideas here to see if I can get it smoothed out.