So Micheal, You have driven your Healey for many miles and were not even aware that your flywheel had been lightened. That tells me that a 29 lb flywheel was not so light that it would be an issue. Based on that information, and the fact that I have a 22 lb flywheel on my BT7 with no adverse effect, I can only assume that a 22 lb flywheel on a 100 motor should work just fine.