340 Engine Shake

Pressure plate, it vibrates at neutral or running down the street correct? Probably pretty bad but seems to go away at higher RPM? Is it unbearable to drive? Dash rattling?

I haven't ran it down the road yet. I put the rear on jack stands to verify clutch engagement and that is when I discovered the driveline shaking like crazy at the pinion. So I removed the driveline, put in a slip yoke and discovered the shake is coming from the engine. So that is where we sit now. I don't want to drive it with the driveline doing what it was doing.