ok, here is what all has been replaced since the vibration started...
new clutch, throw out bearing, resurfaced flywheel, heads reworked, carb rebuilt, new spark plugs, different harmonic balancer, and new motor mounts....
it happens with the clutch in and out but only at higher rpm's. at idle and a little above idle it doesn't vibrate at all.
It's a 440 with a 4 speed behind it. could something be screwed up with the cam, crankshaft, or rods and the motor still run normal (at idle)? it's been over 2 years since we've started messing with this and i just wanna go cruisin around with my dad in our 4 speeds

please ask any and all questions and i'll answer them as soon as i can.
thanks in advance