360 engine vibration

Ok back to the top with this one, oh yes you may have spotted I first raised the issue in Dec 2016! The car is still not on the road, more to do with other projects and helping others rebuild there engines and cars. Anyhow Im back on it now and determined to bottom this issue out.

When I say vibration its like the engine is shaking around as if it has dropped a couple of plugs. If a pull a lead off on eat a time you can here it drop a cylinder but no noticeable difference to the shake.

The compression is good on all cylinders at 150 PSI, the carb has been stripped and rebuilt, its an Elberbrock 1406, the ignition stripped and rebuilt, new plugs,cap rotor arm, leads, pickup, coil converted to GM HEI. I've checked the valve gear, thought I had found the issue one side had the valve rockers LH and RH reversed and push rods rubbing against the head.

the converter appears to have no balance weights and I've fitted the B&M 360 flex plate, strange it has made no difference to the vibration at all before or after.

I haven't driven it on the road as yet but its clear if you hold part throttle at say 1500 to 2000 rpm the engine shakes and you can feel it throughout the body.

If you read back from the start I've also replaced the ripped transmission mount.
Any ideas?