67 Barracuda Formula S 451 - clutch shatter

In reality if it only chatters when in-gauging and you can leave the clutch out slow down till it almost stalls and take off it's not in the drive line it is in the clutch. You have changed everything but the flywheel and nothing fixes it, it has to be the flywheel.

Back in the day before disc brake we had to grind brake drums because the cutting bits would bounce over the hard spots and even after grinding they always came back shaking when trying to stop, the hard spots always come back.