I can't remember exactly when this started, because the car had been put up for about 3 years. I don't remember this being an issue when I put it up, but I cannot say for certain.

I did install a new clutch and had the flywheel turned prior to getting the car ready for the road again. The previous clutch had been soaked by a rear main leak and would shudder when it got up to operating temp. Turning the flywheel and new clutch fixed that problem. Could this have anything to do with it? The flywheel will only install one way.